net/mlx5: fix stack buffer overflow in drop action

net/mlx5: fix stack buffer overflow in drop action

The mlx5_drop_action_create function use mlx5_malloc for allocating
'hrxq', but don't allocate for 'rss_key'. This is wrong and it can
cause buffer overflow.

Detected with address sanitizer:
0 (/usr/lib64/libasan.so.4+0x7b8e2)
1 in mlx5_devx_tir_attr_set ../drivers/net/mlx5/mlx5_devx.c:765
2 in mlx5_devx_hrxq_new ../drivers/net/mlx5/mlx5_devx.c:800
3 in mlx5_devx_drop_action_create ../drivers/net/mlx5/mlx5_devx.c:1051
4 in mlx5_drop_action_create ../drivers/net/mlx5/mlx5_rxq.c:2846
5 in mlx5_dev_spawn ../drivers/net/mlx5/linux/mlx5_os.c:1743
6 in mlx5_os_pci_probe_pf ../drivers/net/mlx5/linux/mlx5_os.c:2501
7 in mlx5_os_pci_probe ../drivers/net/mlx5/linux/mlx5_os.c:2647
8 in mlx5_os_net_probe ../drivers/net/mlx5/linux/mlx5_os.c:2722
9 in drivers_probe ../drivers/common/mlx5/mlx5_common.c:657
10 in mlx5_common_dev_probe ../drivers/common/mlx5/mlx5_common.c:711
11 in mlx5_common_pci_probe ../drivers/common/mlx5/mlx5_common_pci.c:150
12 in rte_pci_probe_one_driver ../drivers/bus/pci/pci_common.c:269
13 in pci_probe_all_drivers ../drivers/bus/pci/pci_common.c:353
14 in pci_probe ../drivers/bus/pci/pci_common.c:380
15 in rte_bus_probe ../lib/eal/common/eal_common_bus.c:72
16 in rte_eal_init ../lib/eal/linux/eal.c:1286
17 in main ../app/test-pmd/testpmd.c:4112

Fixes: 0c762e81da9b ("net/mlx5: share Rx queue drop action code")
Cc: stable@dpdk.org
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>