glsl2: Remove an inlined unvalued return statement.
glsl2: Remove an inlined unvalued return statement.

We already have asserts that it was the last call in the function, so
it's safe to remove after it got cloned in.

Fixes:
glsl-fs-functions-4.

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