net: hns3: Fix cmdq registers initialization issue for vf

According to hardware's description, the head pointer register should
be written before the tail pointer register while initializing the vf
command queue. Otherwise, it may trigger an interrupt even though there
is no command received.

Fixes: fedd0c15 ("net: hns3: Add HNS3 VF IMP(Integrated Management Proc) cmd interface")
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>