arch/frv/kernel/traps.c: using vsnprintf() instead of vsprintf()

Since die_if_kernel() is an extern common used function, better always
check the buffer length to avoid memory overflow by a long 'str'.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/frv/kernel/traps.c

@@ -523,7 +523,7 @@ void die_if_kernel(const char *str, ...)
 		return;
 
 	va_start(va, str);
-	vsprintf(buffer, str, va);
+	vsnprintf(buffer, sizeof(buffer), str, va);
 	va_end(va);
 
 	console_verbose();