net: hibmcge: Add reset supported in this module

Sometimes, if the port doesn't work, we can try to fix it by resetting it.

This patch supports reset triggered by ethtool or FLR of PCIe, For example:
 ethtool --reset eth0 dedicated
 echo 1 > /sys/bus/pci/devices/0000\:83\:00.1/reset

We hope that the reset can be performed only when the port is down,
and the port cannot be up during the reset.
Therefore, the entire reset process is protected by the rtnl lock.

After the reset is complete, the hardware registers are restored
to their default values. Therefore, some rebuild operations are
required to rewrite the user configuration to the registers.

Signed-off-by: Jijie Shao <shaojijie@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241216040532.1566229-7-shaojijie@huawei.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>