media: imx: capture: Pass v4l2_pix_format to __capture_legacy_try_fmt()

The __capture_legacy_try_fmt() function only needs the v4l2_pix_format
embedded in the v4l2_format argument it receives. Pass it the
v4l2_pix_format directly, allowing on caller to allocate a smaller
structure on the stack.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>