staging: mt7621-pci: fix PCIe interrupt mapping

staging: mt7621-pci: fix PCIe interrupt mapping

MT7621 has three assigned interrupts for the pcie. This
interrupts should properly being mapped taking into account
which devices are finally connected in which bus according
to link status. So the irq mappings should be as follows
according to link status (three bits indicating which devices
are link up):

* For PCIe Bus 1 slot 0:
  - status = 0x2 || status = 0x6 => IRQ = pcie1_irq (24).
  - status = 0x4 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie0_irq (23).
* For PCIe Bus 2 slot 0:
  - status = 0x5 || status = 0x6 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie1_irq (24).
* For PCIe Bus 2 slot 1:
  - status = 0x5 || status = 0x6 => IRQ = pcie2_irq (25).
  - default => IRQ = pcie1_irq (24).
* For PCIe Bus 3 any slot:
  - default => IRQ = pcie2_irq (25).

Because of this, the function 'of_irq_parse_and_map_pci' cannot
be used and we need to change device tree information from using
the 'interrupt-map' and 'interrupt-map-mask' properties into an
'interrupts' property to be able to get irq information from the
ports using the 'platform_get_irq' and storing an 'irq-map' into
the pcie driver data node to properly map correct irq using a
new 'mt7621_map_irq' function where this map will be read and the
correct irq returned.

Fixes: 6a054cf2a6dc ("staging: mt7621-pci: improve interrupt mapping")
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Link: https://lore.kernel.org/r/20200413055942.2714-1-sergio.paracuellos@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>