drm/amd/powerplay: Fix NULL pointer deref on driver unbind.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -286,6 +286,12 @@ static int pp_resume(void *handle)
 	return hwmgr_hw_resume(hwmgr);
 }
 
+static int pp_set_clockgating_state(void *handle,
+					  enum amd_clockgating_state state)
+{
+	return 0;
+}
+
 static const struct amd_ip_funcs pp_ip_funcs = {
 	.name = "powerplay",
 	.early_init = pp_early_init,
@@ -300,7 +306,7 @@ static const struct amd_ip_funcs pp_ip_funcs = {
 	.is_idle = pp_is_idle,
 	.wait_for_idle = pp_wait_for_idle,
 	.soft_reset = pp_sw_reset,
-	.set_clockgating_state = NULL,
+	.set_clockgating_state = pp_set_clockgating_state,
 	.set_powergating_state = pp_set_powergating_state,
 };