drivers/i2c/ck505: Add generic driver to configure clockgen

drivers/i2c/ck505: Add generic driver to configure clockgen

Replaces the ics/954309 driver with a more generic version to
accommodate clockgens with a different amount of registers.

It also features a mask to only touch certain bits of the clockgen.

TODO: set appropriate mask for X60/T60 since the datasheets for their
clockgens can be found.

Change-Id: Ie43c4de7891a39f2f443e78213ecd688134e68d7
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/20042
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>