ARM: Marvell: Update PCIe fixup

- The code relies on rc_pci_fixup being called, which only happens
  when CONFIG_PCI_QUIRKS is enabled, so add that to Kconfig. Omitting
  this causes a booting failure with a non-obvious cause.
- Update rc_pci_fixup to set the class properly, copying the
  more modern style from other places
- Correct the rc_pci_fixup comment

This patch just re-applies commit 1dc831bf ("ARM: Kirkwood: Update
PCI-E fixup") for all other Marvell ARM platforms which have same buggy
PCIe controller and do not use pci-mvebu.c controller driver yet.

Long-term goal for these Marvell ARM platforms should be conversion to
pci-mvebu.c controller driver and removal of these fixups in arch code.

Signed-off-by: Pali Rohár <pali@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: stable@vger.kernel.org
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>