Vulkan: Turn 1-view multiview FBOs into no-multiview When only 1 view is enabled, ANGLE continued to append a VkRenderPassMultiviewCreateInfo struct to the render pass. VVL produced an error when transform feedback was used in this case, quoting that multiview and transform feedback cannot mix. This change makes sure that 1-view framebuffers are threated as if they were not multiview. Bug: angleproject:6478 Change-Id: If079c9a052f822342a49a9cc880be2577a356b64 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3206269 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>