[AX.25]: Mark all kmalloc users __must_check

The recent fix 0506d4068bad834aab1141b5dc5e748eb175c6b3 made obvious that
error values were not being propagated through the AX.25 stack.  To help
with that this patch marks all kmalloc users in the AX.25, NETROM and
ROSE stacks as __must_check.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ax25/af_ax25.c b/net/ax25/af_ax25.c
index 6cabf6d..42233df 100644
--- a/net/ax25/af_ax25.c
+++ b/net/ax25/af_ax25.c
@@ -1088,8 +1088,8 @@
 /*
  *	FIXME: nonblock behaviour looks like it may have a bug.
  */
-static int ax25_connect(struct socket *sock, struct sockaddr *uaddr,
-	int addr_len, int flags)
+static int __must_check ax25_connect(struct socket *sock,
+	struct sockaddr *uaddr, int addr_len, int flags)
 {
 	struct sock *sk = sock->sk;
 	ax25_cb *ax25 = ax25_sk(sk), *ax25t;