switch device_get_devnode() and ->devnode() to umode_t *

both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 6d18f35..fe23ee7 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -163,7 +163,7 @@
                                          * disks that can't be partitioned. */
 
 	char disk_name[DISK_NAME_LEN];	/* name of major driver */
-	char *(*devnode)(struct gendisk *gd, mode_t *mode);
+	char *(*devnode)(struct gendisk *gd, umode_t *mode);
 
 	unsigned int events;		/* supported events */
 	unsigned int async_events;	/* async events, subset of all */