drm/amd/display: make dc_set_power_state() return type `void` again

As dc_set_power_state() no longer allocates memory, it's not necessary
to have return types and check return code as it can't fail anymore.

Change it back to `void`.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -2667,11 +2667,6 @@ static void hpd_rx_irq_work_suspend(struct amdgpu_display_manager *dm)
 	}
 }
 
-static int dm_set_power_state(struct dc *dc, enum dc_acpi_cm_power_state power_state)
-{
-	return dc_set_power_state(dc, power_state) ? 0 : -ENOMEM;
-}
-
 static int dm_suspend(void *handle)
 {
 	struct amdgpu_device *adev = handle;
@@ -2707,7 +2702,9 @@ static int dm_suspend(void *handle)
 
 	hpd_rx_irq_work_suspend(dm);
 
-	return dm_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D3);
+	dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D3);
+
+	return 0;
 }
 
 struct drm_connector *
@@ -2901,9 +2898,7 @@ static int dm_resume(void *handle)
 		if (r)
 			DRM_ERROR("DMUB interface failed to initialize: status=%d\n", r);
 
-		r = dm_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D0);
-		if (r)
-			return r;
+		dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D0);
 
 		dc_resume(dm->dc);
 
@@ -2953,9 +2948,7 @@ static int dm_resume(void *handle)
 	}
 
 	/* power on hardware */
-	r = dm_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D0);
-	if (r)
-		return r;
+	 dc_set_power_state(dm->dc, DC_ACPI_CM_POWER_STATE_D0);
 
 	/* program HPD filter */
 	dc_resume(dm->dc);

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -4777,12 +4777,12 @@ void dc_power_down_on_boot(struct dc *dc)
 		dc->hwss.power_down_on_boot(dc);
 }
 
-bool dc_set_power_state(
+void dc_set_power_state(
 	struct dc *dc,
 	enum dc_acpi_cm_power_state power_state)
 {
 	if (!dc->current_state)
-		return true;
+		return;
 
 	switch (power_state) {
 	case DC_ACPI_CM_POWER_STATE_D0:
@@ -4805,8 +4805,6 @@ bool dc_set_power_state(
 
 		break;
 	}
-
-	return true;
 }
 
 void dc_resume(struct dc *dc)

drivers/gpu/drm/amd/display/dc/dc.h

@@ -2294,7 +2294,7 @@ void dc_notify_vsync_int_state(struct dc *dc, struct dc_stream_state *stream, bo
 
 /* Power Interfaces */
 
-bool dc_set_power_state(
+void dc_set_power_state(
 		struct dc *dc,
 		enum dc_acpi_cm_power_state power_state);
 void dc_resume(struct dc *dc);