tgsi/exec: make inputs/outputs optional for compute shaders.
tgsi/exec: make inputs/outputs optional for compute shaders.

compute shaders don't need input/outputs so don't bother
allocating memory for these.

Acked-by: Roland Scheidegger <7d58aee419d6f9201d75517c885374dff5e7d848@vmware.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler