media: vicodec: process all 4 components for RGB32 formats

Only ARGB32-type pixelformat were assumed to have 4 components, which is
wrong since RGB32-type pixelformats may have an alpha channel, so they
should also assume 4 color components.

The XRGB32-type pixelformats really have only 3 color components, but this
complicated matters since that creates strides that are sometimes width * 3
and sometimes width * 4, and in fact this can result in buffer overflows.

Keep things simple by just always processing all 4 color components.

In the future we might want to optimize this again for the XRGB32-type
pixelformats, but for now keep it simple and robust.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org>      # for v5.4 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>