Vulkan: Get rid of X11 include in DisplayVkXcb.cpp Bug: angleproject:8520 Change-Id: Iaa251b0ba2858873b8d22e8f9e5dae7a2567c95e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5273489 Reviewed-by: Geoff Lang <geofflang@chromium.org> Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>