According to the hardware's description, the driver should clear
the command queue's registers when uloading driver. Otherwise,
these existing value may lead the IMP get into a wrong state.

Also this patch adds hclge_cmd_uninit() to do the command queue
uninitialization which includes clearing registers and freeing
memory.

Fixes: 68c0a5c7 ("net: hns3: Add HNS3 IMP(Integrated Mgmt Proc) Cmd Interface Support")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>