glsl/linker: skip inactive explicit locations.
glsl/linker: skip inactive explicit locations.

This fixes a crash in:
GL45-CTS.explicit_uniform_location.subroutine-loc-negative-link-max-num-of-locations

Reviewed-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler