media: camss: add support for V4L2_PIX_FMT_GREY for sdm845 HW

Add this common format to the various format lists relevant to sdm845.

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>