media: rcar-vin: Use correct pixel format when aligning format

When aligning the format the pixel format that is being processed shall
be used to figure out alignment constraints, not the currently active
pixel format. The alignment might be part of a try operation and shall
not be effected by the active format. Fix this by looking at the correct
pixel format.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>