[AX25]: Make ax2asc thread-proof

Ax2asc was still using a static buffer for all invocations which isn't
exactly SMP-safe.  Change ax2asc to take an additional result buffer as
the argument.  Change all callers to provide such a buffer.

Signed-off-by: Ralf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ax25/ax25_uid.c b/net/ax25/ax25_uid.c
index a8b3822..d53cc86 100644
--- a/net/ax25/ax25_uid.c
+++ b/net/ax25/ax25_uid.c
@@ -168,12 +168,14 @@
 
 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 {
+	char buf[11];
+
 	if (v == SEQ_START_TOKEN)
 		seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 	else {
 		struct ax25_uid_assoc *pt = v;
 
-		seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(&pt->call));
+		seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 	}
 	return 0;
 }