drm: ->agp_init can't fail

Thanks to the removal of REQUIRE_AGP we can use a void return value
and shed a bit of complexity.

Reviewed-by: David Herrmann <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/drm_pci.c

···
 	return 0;
 }
 
-static int drm_pci_agp_init(struct drm_device *dev)
+static void drm_pci_agp_init(struct drm_device *dev)
 {
 	if (drm_core_has_AGP(dev)) {
 		if (drm_pci_device_is_agp(dev))
···
 				1024 * 1024);
 		}
 	}
-	return 0;
 }
 
 static void drm_pci_agp_destroy(struct drm_device *dev)

drivers/gpu/drm/drm_stub.c

···
 
 	mutex_lock(&drm_global_mutex);
 
-	if (dev->driver->bus->agp_init) {
-		ret = dev->driver->bus->agp_init(dev);
-		if (ret)
-			goto out_unlock;
-	}
+	if (dev->driver->bus->agp_init)
+		dev->driver->bus->agp_init(dev);
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		ret = drm_get_minor(dev, &dev->control, DRM_MINOR_CONTROL);

include/drm/drmP.h

···
 			  struct drm_unique *unique);
 	int (*irq_by_busid)(struct drm_device *dev, struct drm_irq_busid *p);
 	/* hooks that are for PCI */
-	int (*agp_init)(struct drm_device *dev);
+	void (*agp_init)(struct drm_device *dev);
 	void (*agp_destroy)(struct drm_device *dev);
 
 };