Add the AR933x SoC GPIO pin count limitation.
Add device identification and probe/attach support for the QCA9565.

The QCA9565 is a 1x1 2.4GHz 11n chip with integrated on-chip bluetooth.
The AR9300 HAL already has support for this chip; it just wasn't
included in the probe/attach path.

Tested:

* This commit brought to you over a QCA9565 wifi connection from
  FreeBSD.
* .. ie, basic STA, pings, no iperf or antenna diversity checking just yet.