ilo: refactor blitter_xy_color_blt()
ilo: refactor blitter_xy_color_blt()

Add gen6_XY_COLOR_BLT() and let blitter_xy_color_blt() call the function.  Not
sure if this path is still being hit by any application.

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