CHROMIUM: media: virtio: add support for VIDIOC_TRY_FMT

This patch adds support for previosly unsupported VIDIOC_TRY_FMT ioctl
for encoder and decoder devices. It is implemented using already existing
function virtio_video_try_fmt.

Signed-off-by: Bartłomiej Grzesik <bag@semihalf.com>

BUG=b:160440787
TEST=v4l2-compliance -d /dev/video0
TEST=v4l2-compliance -d /dev/video1
TEST=tast run eve arc.Video*

Change-Id: I4b1e48ef3a8a00a0de9d7ac3983cbe7456bb8060
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3423863


Commit-Queue: Bartłomiej Grzesik <bgrzesik@google.com>
Tested-by: Patryk Busse <pbu@semihalf.com>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Signed-off-by: Slawomir Rosek <srosek@google.com>