[AUDIT] Fix signedness of 'serial' in various routines.

Attached is a patch that corrects a signed/unsigned warning. I also noticed
that we needlessly init serial to 0. That only needs to occur if the kernel
was compiled without the audit system.

-Steve Grubb

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 77e9259..49ecd70 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -992,7 +992,7 @@
 }
 
 void audit_get_stamp(struct audit_context *ctx,
-		     struct timespec *t, int *serial)
+		     struct timespec *t, unsigned int *serial)
 {
 	if (ctx) {
 		t->tv_sec  = ctx->ctime.tv_sec;