virtio: video: make Rect struct comparable
virtio: video: make Rect struct comparable

This is useful for e.g. unit tests.

BUG=b:161774071
TEST=arc.VideoDecodeAccel.h264_vm passes on hatch
TEST=arc.VideoEncodeAccel.h264_360p_i420_vm passes on hatch

Change-Id: Ica409926c9da6c788a60134fa3f609db97f4aaa4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2983092
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Commit-Queue: Alexandre Courbot <301cd6a3ea50a894b4b51e385c5eb12b9a4ffc0c@chromium.org>
Reviewed-by: David Staessens <a4557d4b9b905b8f9d5c87334b8d9f562e1ec119@chromium.org>
Reviewed-by: Keiichi Watanabe <815e4e8f7c92a23424d7c3f51ead622bcedbc720@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm