Fix incorrect quality level with depth-stencil buffer and MSAA configs. Using a depth buffer format requires that the DSV and RTV have equal quality levels; otherwise, the bound render target will discard writes. BUG=angleproject:1917 Change-Id: Ife25b0a8958fa2b31b43a0d877d27e440916a9bf Reviewed-on: https://chromium-review.googlesource.com/560716 Reviewed-by: Bryan Bernhart <bryan.bernhart@intel.com> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>