Fix the RTV and SRV conflict This change fixes below error: Message 0: ID3D11DeviceContext::CSSetShaderResources: Resource being set to CS shader resource slot 0 is still bound on output! Forcing to NULL. Bug: angleproject:3658 Change-Id: I72d656cf61ffb7c39660c019eab980c39eafb70f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1688307 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>