mtd: spi-nor: intel-spi: Convert to SPI MEM

The preferred way to implement SPI-NOR controller drivers is through SPI
subsubsystem utilizing the SPI MEM core functions. This converts the
Intel SPI flash controller driver over the SPI MEM by moving the driver
from SPI-NOR subsystem to SPI subsystem and in one go make it use the
SPI MEM functions. The driver name will be changed from intel-spi to
spi-intel to match the convention used in the SPI subsystem.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mauro Lima <mauro.lima@eclypsium.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20220209122706.42439-3-mika.westerberg@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>