The on-board NIC is an 3x3 AR9380 with 5GHz only.
* enable pci code in AR9344_BASE
* enable ath_pci and the firmware loading bits in DB120
* add in the relevant hints in DB120.hints to inform the probe/attach
code where the PCIe fixup data is for the onboard chip.
This is only relevant for a default development board. I also have a
DB120 with the on-board PCIe wifi NIC disabled and it's exposed as
a real PCIe slot (to put normal PCIe NICs in); the fixup code will need
to be disabled to make this work correctly.
Tested:
* DB120
e952166b53