media: i2c: imx290: Add RAW12 mode support

IMX290 is capable of outputting frames in both Raw Bayer (packed) 10 and
12 bit formats. Since the driver already supports RAW10 mode, let's add
the missing RAW12 mode as well.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>