net: hns3: add reset handling for VF when doing PF reset

When PF performs a function reset, the hardware will reset both PF
and all the VF belong to this PF. Hence, both PF's driver and VF's
driver need to perform corresponding reset operations.

Before PF driver asserting function reset to hardware, it firstly
set up VF's hardware reset status, and inform the VF driver with
HNAE3_VF_PF_FUNC_RESET, then VF driver sets this reset type to
reset_pending and shechule reset task to stop IO and waits for the
hardware reset status to clear. When PF driver has reinitialized the
hardware and is ready to process mailbox from VF, PF driver clears
VF's hardware reset status for VF to continue its reset process.

Also, this patch uses readl_poll_timeout to simplify the hardware reset
status waitting.

Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>