d3d11: Use consistent memory usage/layout in any case

d3d11memory: Always use native DXGI format if device support it

Use consistent memory layout between dxva and other shader use case.
For example, use DXGI_FORMAT_NV12 texture format instead of
two textures with DXGI_FORMAT_R8_UNORM and DXGI_FORMAT_R8G8_UNORM.

Revert "d3d11: Add support for D3D11_USAGE_DYNAMIC"

This reverts commit ddd13fc7c061a9873b181d0de32aaf9546e7d0af

Dynamic usage can reduce the number of copy per frame but make
things complicated and the benefit seems to not significant.
Also since we don't provide _map() method for the dynamic usage,
application cannot read buffers which make "last-sample" property
unusable in case of d3d11videosink.

Closes: #1150 (closed)