[PATCH v2] PCI: dwc: Make Link Up IRQ logic handle already powered on PCIe switches

[Niklas Cassel]

Forgot to pick up tags from v1, adding them here so that e.g. b4 will pick
them up:

Tested-by: Shawn Lin <shawn.lin at rock-chips.com>
Tested-by: FUKAUMI Naoki <naoki at radxa.com>