mesa: Make a shared header for 3D pipeline enum / #defines.

mesa: Make a shared header for 3D pipeline enum / #defines.

NIR uses these enums/#defines in nir_variables and associated intrinsics,
but I want to be able to use them from TGSI->NIR and NIR->TGSI.
Otherwise, we had to pull in all of mtypes.h.

This doesn't cover all of the enums we might want from a shared compiler
core (like varying slots or vert attribs), but it at least covers what I
need at the moment (system values and interp qualifiers).

v2: Move to src/glsl since util/ is really vague.  Include in Makefile.am
    list.  Use plain bitshifts and stdint types instead of undefined
    BITFIELD64_BIT.
v3: Rename to shader_enums.h. Move it into Makefile.sources.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v2, with
             recommendation to rename)