st/glsl_to_tgsi: don't increase immediate index by 1.
Immediates are stored into a separate table, and are
consolidated, so if we get an immediate we don't need
to offset it as the index it has is correct.
Cc: "11.2 12.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by:
Dave Airlie <airlied@redhat.com>