d3d12: Do not use PIPE_BIND_DISPLAY_TARGET for d3d12_video_buffer
Do not use PIPE_BIND_DISPLAY_TARGET
when creating the underlying resource in d3d12_video_buffer
.
Prevents an issue where using such bind flag will hit assert(res->base.b.format == PIPE_FORMAT_R16G16B16A16_FLOAT)
on video buffer creation on debug builds.