Bluetooth: Add BUILD_BUG_ON for size of struct sockaddr_rc

This adds an extra check for ensuring that the size of sockaddr_rc
does not grow larger than sockaddr.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index 2348176..d8a9575 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -1058,6 +1058,8 @@
 {
 	int err;
 
+	BUILD_BUG_ON(sizeof(struct sockaddr_rc) > sizeof(struct sockaddr));
+
 	err = proto_register(&rfcomm_proto, 0);
 	if (err < 0)
 		return err;