usb: musb: am335x: add second port to beagle bone

So I assumed that Beagle bone has only one USB port in host mode because
the micro USB connector had an USB-UART there. I was wrong a little. The
second port runs on host mode, but the micro USB plug is connected to an
internal HUB with two ports: one to the USB-UART and one to musb
instance one.
For that reason, this patch enables both ports: the primary in device
mode only and the second in host mode only.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>