drm/amdgpu/powerplay: return success if set_mp1_state is not set

Some asics (APUs) don't have this callback so we want to return
success.  Avoids spurious error messages on APUs.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/amd_powerplay.c

@@ -931,12 +931,10 @@ static int pp_dpm_set_mp1_state(void *handle, enum pp_mp1_state mp1_state)
 	if (!hwmgr || !hwmgr->pm_en)
 		return -EINVAL;
 
-	if (hwmgr->hwmgr_func->set_mp1_state == NULL) {
-		pr_info_ratelimited("%s was not implemented.\n", __func__);
-		return -EINVAL;
-	}
-
+	if (hwmgr->hwmgr_func->set_mp1_state)
 		return hwmgr->hwmgr_func->set_mp1_state(hwmgr, mp1_state);
+
+	return 0;
 }
 
 static int pp_dpm_switch_power_profile(void *handle,