net: hns3: Changes to make enet watchdog timeout func common for PF/VF

HNS3 drivers enet layer, used for the ring management and stack
interaction, is common to both VF and PF. PF already supports reset
functionality to handle the network stack watchdog timeout trigger
but the existing code is not generic enough to be used to support VF
reset as well.
This patch does following:
1. Makes the existing watchdog timeout handler in enet layer generic
   i.e. suitable for both VF and PF and
2. Introduces the new reset event handler for the VF code.
3. Changes existing reset event handler of PF code to initialize the
   reset level

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