wined3d: Rename IWineD3DImpl_IsPixelFormatCompatibleWithRenderFmt() to wined3d_check_pixel_format_color().

To avoid reloading it all the time.

wined3d: Rename IWineD3DImpl_IsPixelFormatCompatibleWithDepthFmt to wined3d_check_pixel_format_depth().

This also changes the texture level to always be zero while we're at it. In
practice depth/stencil textures should rarely have multiple levels, if ever,
but only 0 makes sense here.