[Vulkan] Enable kRGB_888x_SkColorType in SkColorTypeToVkFormat()

Previously, gfx::SkColorTypeToVkFormat() wasn't mapping
kRGB_888x_SkColorType because VK_FORMAT_R8G8B8_UNORM was not supported
by Skia, but it should be able to handle that image format now.

Bug: 861853
Change-Id: Ic2b861f42628946484efb872aaf0c43aad5d660b
Reviewed-on: https://chromium-review.googlesource.com/c/1372724
Reviewed-by: Michael Spang <spang@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615808}
1 file changed