radeonsi: don't force gl_SampleMaskIn to 1 for smoothing
radeonsi: don't force gl_SampleMaskIn to 1 for smoothing

Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler