image: fix legal types for packed integer formats.
image: fix legal types for packed integer formats.

After reading ARB_texture_rgb10_a2ui it appears the packed formats
for integer types are only specified via this extension, and not via
the original ones. So condition the checks on this.

Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>
Reviewed-by: Eric Anholt <96f164ad4d9b2b0dacf8ebee2bb1eeb3aa69adf1@anholt.net>

zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,mapbox/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,mapbox/glsl-optimizer,zz85/glsl-optimizer,zz85/glsl-optimizer,bkaradzic/glsl-optimizer,mapbox/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer,dellis1972/glsl-optimizer,zeux/glsl-optimizer,benaadams/glsl-optimizer,jbarczak/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,djreep81/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,zz85/glsl-optimizer,dellis1972/glsl-optimizer,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,jbarczak/glsl-optimizer,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,zeux/glsl-optimizer,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,mcanthony/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,wolf96/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,benaadams/glsl-optimizer,djreep81/glsl-optimizer,jbarczak/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,zz85/glsl-optimizer