i965/fs: Disable unlit_centroid_workaround on Haswell.
i965/fs: Disable unlit_centroid_workaround on Haswell.

Although the HSW PRM shows it, the BSpec lists this workaround as being
for Ivybridge only.

total instructions in shared programs: 1994951 -> 1993675 (-0.06%)
instructions in affected programs:     27325 -> 26049 (-4.67%)

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