Vulkan: get render target format from config Instead of hardcoded GL_BGRA8_EXT. Also change renderTargetFormat to GL_BGRA8_EXT in DisplayVk::generateConfigs() BUG=angleproject:2314 Change-Id: I47471add4e681fd0b8101d475c4a33ab59920c5c Reviewed-on: https://chromium-review.googlesource.com/881952 Commit-Queue: Yuly Novikov <ynovikov@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>