util: Fix swizzles for SRGB formats.
util: Fix swizzles for SRGB formats.

Based on Marek Olšák's fix 8-bits-per-channel formats swizzles, with the
exception that the notation for several formats (the vector formats)
is actually reversed so they should be left alone.

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