direct3d11: only change the pixel shader if the first output texture is DXGI_FORMAT_R8_UNORM
direct3d11: only change the pixel shader if the first output texture is DXGI_FORMAT_R8_UNORM

Signed-off-by: Jean-Baptiste Kempf <7b85a41a628204b76aba4326273a3ccc74bd009a@videolan.org>

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc