As per spec, the CAPTURE resolution should be automatically set based on the
OTUPUT resolution. This patch properly propagate width/height to the capture
when the OUTPUT format is set and override the user provided width/height with
configured OUTPUT resolution when the CAPTURE fmt is updated.

This also prevents userspace from selecting a CAPTURE resolution that is too
small, avoiding unwanted page faults.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>