drm/armada: add IRQ support back

Add IRQ support back so that vblank ioctls work again.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/gpu/drm/armada/armada_drv.c b/drivers/gpu/drm/armada/armada_drv.c
index e2d5792..9110738 100644
--- a/drivers/gpu/drm/armada/armada_drv.c
+++ b/drivers/gpu/drm/armada/armada_drv.c
@@ -190,6 +190,7 @@
 	if (ret)
 		goto err_comp;
 
+	dev->irq_enabled = true;
 	dev->vblank_disable_allowed = 1;
 
 	ret = armada_fbdev_init(dev);
@@ -330,7 +331,7 @@
 	.desc			= "Armada SoC DRM",
 	.date			= "20120730",
 	.driver_features	= DRIVER_GEM | DRIVER_MODESET |
-				  DRIVER_PRIME,
+				  DRIVER_HAVE_IRQ | DRIVER_PRIME,
 	.ioctls			= armada_ioctls,
 	.fops			= &armada_drm_fops,
 };