drm/radeon/dpm: add a late enable callback

Certain features need to be enabled after ring tests
(e.g., powergating, etc.).  Add a function pointer
to split out late enable features.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index 384758d..d4e5bcf 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -1288,6 +1288,18 @@
 		return radeon_pm_init_old(rdev);
 }
 
+int radeon_pm_late_init(struct radeon_device *rdev)
+{
+	int ret = 0;
+
+	if (rdev->pm.pm_method == PM_METHOD_DPM) {
+		mutex_lock(&rdev->pm.mutex);
+		ret = radeon_dpm_late_enable(rdev);
+		mutex_unlock(&rdev->pm.mutex);
+	}
+	return ret;
+}
+
 static void radeon_pm_fini_old(struct radeon_device *rdev)
 {
 	if (rdev->pm.num_power_states > 1) {