svga: relax restriction of compressed formats for texture upload

svga: relax restriction of compressed formats for texture upload

This patch relaxes the restriction of compressed formats for texture
upload buffer. For now, 3D texture with compressed format
is still not supported in the texture upload buffer path.

As Brian noted, ETQW does many texture updates with glCompressedTexSubImage.
This patch greatly improves the performance of the ETQW trace.

Tested with ETQW, MTT piglit, glretrace, conform, viewperf

v2: Per Brian's suggestion, removed the subregion boundary check.

Reviewed-by: Brian Paul <brianp@vmware.com>