i2c: /pasemi: PASemi I2C controller IRQ enablement

This patch adds IRQ support to the PASemi I2C controller driver to
increase the performace of I2C transactions on platforms with PASemi I2C
controllers. While primarily intended for Apple silicon platforms, this
patch should also help in enabling IRQ support for older PASemi hardware
as well should the need arise.

This version of the patch has been tested on an M1 Ultra Mac Studio,
as well as an M1 MacBook Pro, and userspace launches successfully
while using the IRQ path for I2C transactions.

Signed-off-by: Arminder Singh <arminders208@outlook.com>
Reviewed-by: Sven Peter <sven@svenpeter.dev>
Reviewed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: pasemi: Set enable bit for Apple variant

Some later revisions after the original PASemi I2C controller introduce
what likely is an enable bit to the CTL register. Without setting it the
actual i2c transmission is never started.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Acked-by: Olof Johansson <olof@lixom.net>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: pasemi: Refactor _probe to use devm_*

Using managed device resources means there's nothing left to be done in
pasemi_smb_pci_remove and also allows to remove base and size from
struct pasemi_smbus.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Acked-by: Olof Johansson <olof@lixom.net>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: pasemi: Allow to configure bus frequency

Right now the bus frequency has always been hardcoded as
100 KHz with the specific reference clock used in the PASemi
PCI controllers. Make this configurable to prepare for the
platform driver.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Acked-by: Olof Johansson <olof@lixom.net>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: pasemi: Split pci driver to its own file

Split off the PCI driver so that we can reuse common code for the
platform driver.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
Acked-by: Olof Johansson <olof@lixom.net>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>