LSM: do not initialize common_audit_data to 0

It isn't needed.  If you don't set the type of the data associated with
that type it is a pretty obvious programming bug.  So why waste the cycles?

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index c04eea2..cd91e25 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -469,7 +469,7 @@
 
 	if (!a) {
 		a = &stack_data;
-		COMMON_AUDIT_DATA_INIT(a, LSM_AUDIT_DATA_NONE);
+		a->type = LSM_AUDIT_DATA_NONE;
 		a->selinux_audit_data = &sad;
 	}