gma500: make init_pm callback in struct psb_op optional

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/gma500/oaktrail_device.c

@@ -176,10 +176,6 @@ int oaktrail_backlight_init(struct drm_device *dev)
  *	for power management
  */
 
-static void oaktrail_init_pm(struct drm_device *dev)
-{
-}
-
 /**
  *	oaktrail_save_display_registers	-	save registers lost on suspend
  *	@dev: our DRM device
@@ -504,7 +500,6 @@ const struct psb_ops oaktrail_chip_ops = {
 	.backlight_init = oaktrail_backlight_init,
 #endif
 
-	.init_pm = oaktrail_init_pm,
 	.save_regs = oaktrail_save_display_registers,
 	.restore_regs = oaktrail_restore_display_registers,
 	.power_down = oaktrail_power_down,

drivers/gpu/drm/gma500/power.c

@@ -58,6 +58,7 @@ void gma_power_init(struct drm_device *dev)
 	spin_lock_init(&power_ctrl_lock);
 	mutex_init(&power_mutex);
 
+	if (dev_priv->ops->init_pm)
 		dev_priv->ops->init_pm(dev);
 }