net:hns: Add the init code to disable Hip06 "Hardware VLAN assist"

This patch adds the initializzation code to disable the hardware
vlan support for VLAN Tag stripping by default for now.

Proper support of "hardware VLAN assitance" feature would
soon come in the next coming patches.

Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>