net: hns3: add handler for NCSI error mailbox

When NCSI has HW error, the IMP will report this error to the driver
by sending a mailbox. After received this message, the driver should
assert a global reset to fix this kind of HW error.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Reviewed-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>