gallivm: (trivial) fix the logic deciding if function call should be used...
gallivm: (trivial) fix the logic deciding if function call should be used...

Copy and paste bug with the img filter decision. Since there's only 2 different
filters anyway just drop this bit.

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler