media: v4l2: Fix fourcc names for BAYER12P

Fix documentation fourcc names for the 12-bit packed Bayer formats.

Signed-off-by: Daniel Gomez <daniel@qtec.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>