[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/rose/rose_subr.c b/net/rose/rose_subr.c
index a29a3a9..02891ce 100644
--- a/net/rose/rose_subr.c
+++ b/net/rose/rose_subr.c
@@ -400,6 +400,7 @@
 {
 	unsigned char *p = buffer + 1;
 	char *callsign;
+	char buf[11];
 	int len, nb;
 
 	/* National Facilities */
@@ -456,7 +457,7 @@
 
 	*p++ = FAC_CCITT_DEST_NSAP;
 
-	callsign = ax2asc(&rose->dest_call);
+	callsign = ax2asc(buf, &rose->dest_call);
 
 	*p++ = strlen(callsign) + 10;
 	*p++ = (strlen(callsign) + 9) * 2;		/* ??? */
@@ -471,7 +472,7 @@
 
 	*p++ = FAC_CCITT_SRC_NSAP;
 
-	callsign = ax2asc(&rose->source_call);
+	callsign = ax2asc(buf, &rose->source_call);
 
 	*p++ = strlen(callsign) + 10;
 	*p++ = (strlen(callsign) + 9) * 2;		/* ??? */