iio: imu: bno055: serdev requires REGMAP

There are a ton of build errors when REGMAP is not set, so select
REGMAP to fix all of them.

Examples (not all of them):

../drivers/iio/imu/bno055/bno055_ser_core.c:495:15: error: variable 'bno055_ser_regmap_bus' has initializer but incomplete type
495 | static struct regmap_bus bno055_ser_regmap_bus = {
../drivers/iio/imu/bno055/bno055_ser_core.c:496:10: error: 'struct regmap_bus' has no member named 'write'
496 | .write = bno055_ser_write_reg,
../drivers/iio/imu/bno055/bno055_ser_core.c:497:10: error: 'struct regmap_bus' has no member named 'read'
497 | .read = bno055_ser_read_reg,
../drivers/iio/imu/bno055/bno055_ser_core.c: In function 'bno055_ser_probe':
../drivers/iio/imu/bno055/bno055_ser_core.c:532:18: error: implicit declaration of function 'devm_regmap_init'; did you mean 'vmem_map_init'? [-Werror=implicit-function-declaration]
532 | regmap = devm_regmap_init(&serdev->dev, &bno055_ser_regmap_bus,
../drivers/iio/imu/bno055/bno055_ser_core.c:532:16: warning: assignment to 'struct regmap *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
532 | regmap = devm_regmap_init(&serdev->dev, &bno055_ser_regmap_bus,
../drivers/iio/imu/bno055/bno055_ser_core.c: At top level:
../drivers/iio/imu/bno055/bno055_ser_core.c:495:26: error: storage size of 'bno055_ser_regmap_bus' isn't known
495 | static struct regmap_bus bno055_ser_regmap_bus = {

Fixes: 2eef5a9cc643 ("iio: imu: add BNO055 serdev driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrea Merello <andrea.merello@iit.it>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-iio@vger.kernel.org
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20240110185611.19723-1-rdunlap@infradead.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: imu: bno055: Fix missing Kconfig dependencies

This driver uses IIO triggered buffers so it needs to select them in
Kconfig.

on riscv-32bit:

/opt/crosstool/gcc-13.2.0-nolibc/riscv32-linux/bin/riscv32-linux-ld: drivers/iio/imu/bno055/bno055.o: in function `.L367':
bno055.c:(.text+0x2c96): undefined reference to `devm_iio_triggered_buffer_setup_ext'

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Closes: https://lore.kernel.org/linux-next/40566b4b-3950-81fe-ff14-871d8c447627@infradead.org/
Fixes: 4aefe1c2bd0c ("iio: imu: add Bosch Sensortec BNO055 core driver")
Cc: Andrea Merello <andrea.merello@iit.it>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20230903113052.846298-1-jic23@kernel.org
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: imu: add BNO055 I2C driver

Add an I2C driver for communicating to a BNO055 IMU via I2C bus and enable
the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220907132205.28021-14-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: imu: add BNO055 serdev driver

Add a serdev driver for communicating to a BNO055 IMU via serial bus, and
enable the BNO055 core driver to work in this scenario.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Link: https://lore.kernel.org/r/20220907132205.28021-13-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: imu: add Bosch Sensortec BNO055 core driver

Add the core driver for the BNO055 IMU from Bosch. This IMU can be
connected via both serial and I2C busses; separate patches will add support
for them.

The driver supports "AMG" (Accelerometer, Magnetometer, Gyroscope) mode,
that provides raw data from the said internal sensors, and a couple of
"fusion" modes (i.e. the IMU also does calculations in order to provide
euler angles, quaternions, linear acceleration and gravity measurements).

In fusion modes the AMG data is still available (with some calibration
refinements done by the IMU), but certain settings such as low pass filters
cut-off frequency and sensors' ranges are fixed, while in AMG mode they can
be customized; this is why AMG mode can still be interesting.

Signed-off-by: Andrea Merello <andrea.merello@iit.it>
Link: https://lore.kernel.org/r/20220907132205.28021-9-andrea.merello@iit.it
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>