net/hns3: fix some incomplete command structures

net/hns3: fix some incomplete command structures

The descriptor of the command between firmware and driver consists of
8-byte header and 24-byte data field. The contents sent to firmware are
packaged into a command structure as the data field of command
descriptor.

There are some command structures in hns3_dcb.h file that are less than
24 byte. So this patch fixes these incomplete command structures.

Fixes: 62e3ccc2b94c ("net/hns3: support flow control")
Cc: stable@dpdk.org
Signed-off-by: Huisong Li <lihuisong@huawei.com>
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>