nir/lower_io: add nir_intrinsic_load_input_vertex to is_input()

To add the const offset to the base index.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23254>

src/compiler/nir/nir_lower_io.c

@@ -2778,6 +2778,7 @@ static bool
 is_input(nir_intrinsic_instr *intrin)
 {
    return intrin->intrinsic == nir_intrinsic_load_input ||
+          intrin->intrinsic == nir_intrinsic_load_input_vertex ||
           intrin->intrinsic == nir_intrinsic_load_per_vertex_input ||
           intrin->intrinsic == nir_intrinsic_load_interpolated_input ||
           intrin->intrinsic == nir_intrinsic_load_fs_input_interp_deltas;