media: vicodec: Add support for 4 planes formats

Add support for formats with 4 planes: V4L2_PIX_FMT_ABGR32,
V4L2_PIX_FMT_ARGB32.
Also add alpha plane related flags to the header of the encoded file.

Signed-off-by: Dafna Hirschfeld <dafna3@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
[hans.verkuil@cisco.com: fix line-too-long warnings]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>