r600: handle barrier opcode.
r600: handle barrier opcode.

This handles the barrier opcode for EG/CM.

Signed-off-by: Edward O'Callaghan <117173807d5a49976a891944633465c0daea7f98@alterapraxis.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler