[media] bfin_capture: fix compiler warning

media-git/drivers/media/platform/blackfin/bfin_capture.c: In function ‘bcap_probe’:
media-git/drivers/media/platform/blackfin/bfin_capture.c:1007:16: warning: ignoring return value of ‘vb2_queue_init’, declared with attribute warn_unused_result [-Wunused-result]
  vb2_queue_init(q);
                  ^

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Scott Jiang <scott.jiang.linux@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>