* Override the TX/RX stream count if the EEPROM reports a single RX or
TX stream, rather than assuming the device will always be a 2x2 strea
device.
* For AR9280 devices, don't hard-code 2x2 stream. Instead, allow the
ar5416FillCapabilityInfo() routine to correctly determine things.
The latter should be done for all 11n chips now that
ar5416FillCapabilityInfo() will set the TX/RX stream count based on the
active TX/RX chainmask in the EEPROM.
Thanks to Maciej Milewski for donating some AR9281 NICs to me for
testing.