st/mesa: update comment in st_atom_msaa.c
st/mesa: update comment in st_atom_msaa.c

The old comment was a copy and paste mistake.  Indent another comment.

Reviewed-by: Roland Scheidegger <7d58aee419d6f9201d75517c885374dff5e7d848@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler