CHROMIUM: media: virtio: handle minimum frame rate equal to 0

Before this patch v4l2-compliance was failing when hypervisor reported
allowed minimum frame rate equal to zero for encoder device.

This patch fixes this issue, but returning a fraction with numerator
set to 1 and denumator set to U32_MAX in case of minimum frame rate
equal to zero.

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

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

Change-Id: Ic805e46468a3fbfd4426d16e96cee531dd26bad1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3429242


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