drm/amd/powerplay: don't give up if DPM is already running

Currently the driver crashes if smu7_enable_dpm_tasks() returns early,
which it does if DPM is already active. It seems to be better just to
continue anyway, at least I haven't noticed any ill effects. It's also
unclear at what state the hardware was left by the previous driver, so
IMO it's better to always fully initialize.

Way to reproduce:
with GPU passthrough.
forced power off the VM or forced reset the VM
without shutting down the Os.

Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c

@@ -1168,8 +1168,8 @@ int smu7_enable_dpm_tasks(struct pp_hwmgr *hwmgr)
 
 	tmp_result = (!smum_is_dpm_running(hwmgr)) ? 0 : -1;
 	PP_ASSERT_WITH_CODE(tmp_result == 0,
-			"DPM is already running right now, no need to enable DPM!",
-			return 0);
+			"DPM is already running",
+			);
 
 	if (smu7_voltage_control(hwmgr)) {
 		tmp_result = smu7_enable_voltage_control(hwmgr);