Fix the example of the V4L2_PIX_FMT_SGRBG8 Bayer format.

The even lines should read BGBG, not RBRB.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>