drm/nouveau/pm: make clocks_set return an error code clocks_set can fail.

Reporting an error is better than silently refusing to reclock.

V2: Use the same logic on nv40

Signed-off-by: Martin Peres <martin.peres@labri.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv40_pm.c b/drivers/gpu/drm/nouveau/nv40_pm.c
index 02d5be8..3d5a5a7 100644
--- a/drivers/gpu/drm/nouveau/nv40_pm.c
+++ b/drivers/gpu/drm/nouveau/nv40_pm.c
@@ -222,7 +222,7 @@
 	return true;
 }
 
-void
+int
 nv40_pm_clocks_set(struct drm_device *dev, void *pre_state)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
@@ -231,7 +231,7 @@
 	struct bit_entry M;
 	u32 crtc_mask = 0;
 	u8 sr1[2];
-	int i;
+	int i, ret = -EAGAIN;
 
 	/* determine which CRTCs are active, fetch VGA_SR1 for each */
 	for (i = 0; i < 2; i++) {
@@ -263,6 +263,8 @@
 	if (!nv_wait_cb(dev, nv40_pm_gr_idle, dev))
 		goto resume;
 
+	ret = 0;
+
 	/* set engine clocks */
 	nv_mask(dev, 0x00c040, 0x00000333, 0x00000000);
 	nv_wr32(dev, 0x004004, info->npll_coef);
@@ -345,6 +347,7 @@
 	spin_unlock_irqrestore(&dev_priv->context_switch_lock, flags);
 
 	kfree(info);
+	return ret;
 }
 
 int