Vulkan: populate ycbcr conversionDesc for yuv VkFormats For this case, the external format has a vulkan equivalent VkFormat and is YUV, so conversionDesc needs to be populated. YcbcrConversionDesc::update() expects externalFormat to be 0 in this case since it has an equivalent. Bug: b/368429977 Bug: b/352595520 Change-Id: Ifdae7a539555d78bbbf9d11cdbb946cb815c7709 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5896250 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com>