glsl: count attributes for vertex inputs properly.
glsl: count attributes for vertex inputs properly.

This function deals with vertex inputs and fragment
outputs, so we should count the attribute locations
correctly for the vertex inputs.

Reviewed-by: Timothy Arceri <5dd83789ef3714029244367ba1ca09f1d7627408@collabora.com>
Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler