mm-video: vdec: fix multiple downscalar issues

-In set_parameter for output port with new resolution,
 ignore buffer size and count mismatch.
-In set_parameter for input port, do not call get_buffer_req
 for output port.
-In update_portdef, port definition values are fetched from
 driver using ioctl.
-Crop rectangle is updated during set param for output port
 instead of during update_res.

CRs-Fixed: 629474
Change-Id: I0d1ca6b8b170ded07bee6c48c5370d7386f0639b
1 file changed