media: imx: Set capture compose rectangle in capture_device_set_format

The capture compose rectangle was not getting updated when setting
the source subdevice's source pad format. This causes the compose window
to be zero (or not updated) at stream start unless the capture device
format was set explicitly at the capture device node.

Fix by moving the calculation of the capture compose rectangle to
imx_media_mbus_fmt_to_pix_fmt(), and pass the rectangle to
imx_media_capture_device_set_format().

Fixes: 439d8186 ("media: imx: add capture compose rectangle")

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>