Revert "r600g: Don't negate result of ABS instruction"
Revert "r600g: Don't negate result of ABS instruction"

This reverts commit b6d40213935da702570eca2c0861bd4b1d7f5254.

This actually breaks gears here on my rv670.

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