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>

drivers/base/devtmpfs.c

@@ -40,7 +40,7 @@ static struct req {
 	struct completion done;
 	int err;
 	const char *name;
-	mode_t mode;	/* 0 => delete */
+	umode_t mode;	/* 0 => delete */
 	struct device *dev;
 } *requests;