audit: use audit_set_enabled() in audit_enable()

Use audit_set_enabled() to enable auditing during early boot.  This
obviously won't emit an audit change record, but it will work anyway
and should help prevent in future problems by consolidating the
enable/disable code in one function.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

kernel/audit.c

@@ -1575,8 +1575,8 @@ static int __init audit_enable(char *str)
 
 	if (audit_default == AUDIT_OFF)
 		audit_initialized = AUDIT_DISABLED;
-	audit_enabled = audit_default;
-	audit_ever_enabled = !!audit_enabled;
+	if (audit_set_enabled(audit_default))
+		panic("audit: error setting audit state (%d)\n", audit_default);
 
 	pr_info("%s\n", audit_default ?
 		"enabled (after initialization)" : "disabled (until reboot)");