RDMA/mlx5: Signedness bug in UVERBS_HANDLER()

The "num_actions" variable needs to be signed for the error handling to
work.  The maximum number of actions is less than 256 so int type is large
enough for that.

Fixes: cbfdd442c4 ("IB/uverbs: Add helper to get array size from ptr attribute")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx5/flow.c

@@ -329,7 +329,7 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_FLOW_ACTION_CREATE_MODIFY_HEADER)(
 	struct mlx5_ib_dev *mdev = to_mdev(uobj->context->device);
 	enum mlx5_ib_uapi_flow_table_type ft_type;
 	struct ib_flow_action *action;
-	size_t num_actions;
+	int num_actions;
 	void *in;
 	int ret;