selftests/net: Add missing va_end.

There is no va_end after va_copy, just add it.

Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240927040050.7851-1-zhangjiao2@cmss.chinamobile.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/tcp_ao/lib/aolib.h

@@ -46,6 +46,7 @@ static inline char *test_snprintf(const char *fmt, va_list vargs)
 
 	va_copy(tmp, vargs);
 	n = vsnprintf(ret, size, fmt, tmp);
+	va_end(tmp);
 	if (n < 0)
 		return NULL;