include/uapi/linux/openvswitch.h: use __u32 from linux/types.h

Fixes userspace compiler error:

error: unknown type name ‘uint32_t’
Signed-off-by: Mikko Rapeli <mikko.rapeli@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/openvswitch.h

@@ -632,8 +632,8 @@ enum ovs_hash_alg {
  * @hash_basis: basis used for computing hash.
  */
 struct ovs_action_hash {
-	uint32_t  hash_alg;     /* One of ovs_hash_alg. */
-	uint32_t  hash_basis;
+	__u32  hash_alg;     /* One of ovs_hash_alg. */
+	__u32  hash_basis;
 };
 
 /**