gro: fix missing includes

The GRO header file depends on stdint and mbuf.

Spotted with devtools/check-includes.sh

Fixes: e996506a1c07 ("lib/gro: add Generic Receive Offload API framework")

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: John McNamara <john.mcnamara@intel.com>

lib/librte_gro/rte_gro.h

@@ -38,6 +38,9 @@
  * Interface to GRO library
  */
 
+#include <stdint.h>
+#include <rte_mbuf.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif