media: i2c: gc2145: addition of RAW8 formats support

Adds support for RAW8 formats (BGGR/RGGB/RBRG/BRBG).

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: fix typo: colospace -> colorspace]