net: hns3: optimize the filter table entries handling when resetting

Currently, the PF driver removes all (including its VFs') MAC/VLAN
flow director table entries when resetting, and restores them after
reset completed.

In fact, the hardware will clear all table entries only in IMP
reset and global reset. So driver only needs to restore the table
entries in these cases, and needs do nothing when PF reset, FLR
or other function level reset.

This patch optimizes it by removing unnecessary table entries clear
and restoring handling in the reset flow, and doing the restoring
after reset completed.

Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>