glsl: Optionally lower TES gl_PatchVerticesIn to a uniform.

glsl: Optionally lower TES gl_PatchVerticesIn to a uniform.

i965 has no special hardware for this, so we need to pass this value in
as a uniform (unless the TES is linked against a TCS, in which case the
linker can just replace this with a constant).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Cc: mesa-stable@lists.freedesktop.org