fix: zink: unused variable ‘intr’ [-Wunused-variable]

Only used in debug builds.

Signed-off-by: Kai Wasserbäch <kai@dev.carbon-project.org>
Reviewed-by: Mihai Preda <mhpreda@gmail.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18643>

src/gallium/drivers/zink/zink_compiler.c

@@ -2846,7 +2846,7 @@ is_residency_code(nir_ssa_def *src)
    nir_instr *parent = src->parent_instr;
    while (1) {
       if (parent->type == nir_instr_type_intrinsic) {
-         nir_intrinsic_instr *intr = nir_instr_as_intrinsic(parent);
+         ASSERTED nir_intrinsic_instr *intr = nir_instr_as_intrinsic(parent);
          assert(intr->intrinsic == nir_intrinsic_is_sparse_texels_resident);
          return false;
       }