mesa: fix material inputs in ffvertex_prog.c
mesa: fix material inputs in ffvertex_prog.c

Varying material inputs were not being picked up from the same slots
where the VBO code is currently placing them (GENERIC0 and above).
Most often they were just being ignored.

mcanthony/glsl-optimizer,tokyovigilante/glsl-optimizer,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,jbarczak/glsl-optimizer,benaadams/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,benaadams/glsl-optimizer,zeux/glsl-optimizer,dellis1972/glsl-optimizer,dellis1972/glsl-optimizer,metora/MesaGLSLCompiler,mcanthony/glsl-optimizer,zz85/glsl-optimizer,adobe/glsl2agal,jbarczak/glsl-optimizer,wolf96/glsl-optimizer,mcanthony/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,metora/MesaGLSLCompiler,adobe/glsl2agal,jbarczak/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,wolf96/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,tokyovigilante/glsl-optimizer,KTXSoftware/glsl2agal,mcanthony/glsl-optimizer,zeux/glsl-optimizer,wolf96/glsl-optimizer,bkaradzic/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,KTXSoftware/glsl2agal,adobe/glsl2agal,dellis1972/glsl-optimizer,mapbox/glsl-optimizer,KTXSoftware/glsl2agal,mcanthony/glsl-optimizer,mapbox/glsl-optimizer,KTXSoftware/glsl2agal,zz85/glsl-optimizer,benaadams/glsl-optimizer,adobe/glsl2agal,adobe/glsl2agal,KTXSoftware/glsl2agal,wolf96/glsl-optimizer,tokyovigilante/glsl-optimizer,jbarczak/glsl-optimizer,zz85/glsl-optimizer,zeux/glsl-optimizer,bkaradzic/glsl-optimizer,zz85/glsl-optimizer,djreep81/glsl-optimizer,djreep81/glsl-optimizer,metora/MesaGLSLCompiler,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,djreep81/glsl-optimizer,dellis1972/glsl-optimizer,bkaradzic/glsl-optimizer,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer