drm/i915/selftest: fix intel_selftest_modify_policy argument types

The definition of intel_selftest_modify_policy() does not match the
declaration, as gcc-13 points out:

drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c:29:5: error: conflicting types for 'intel_selftest_modify_policy' due to enum/integer mismatch; have 'int(struct intel_engine_cs *, struct intel_selftest_saved_policy *, u32)' {aka 'int(struct intel_engine_cs *, struct intel_selftest_saved_policy *, unsigned int)'} [-Werror=enum-int-mismatch]
   29 | int intel_selftest_modify_policy(struct intel_engine_cs *engine,
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c:11:
drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.h:28:5: note: previous declaration of 'intel_selftest_modify_policy' with type 'int(struct intel_engine_cs *, struct intel_selftest_saved_policy *, enum selftest_scheduler_modify)'
   28 | int intel_selftest_modify_policy(struct intel_engine_cs *engine,
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change the type in the definition to match.

Fixes: 617e87c0 ("drm/i915/selftest: Fix hangcheck self test for GuC submission")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230117163743.1003219-1-arnd@kernel.org

drivers/gpu/drm/i915/selftests/intel_scheduler_helpers.c

@@ -28,8 +28,7 @@ struct intel_engine_cs *intel_selftest_find_any_engine(struct intel_gt *gt)
 
 int intel_selftest_modify_policy(struct intel_engine_cs *engine,
 				 struct intel_selftest_saved_policy *saved,
-				 u32 modify_type)
-
+				 enum selftest_scheduler_modify modify_type)
 {
 	int err;