svga: add guest statistic gathering interface
svga: add guest statistic gathering interface

This file was supposed to be added with the previous "svga: add guest
statistic gathering interface" patch but went MIA for some reason.

Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler