This patch limits the drawn USB current to 100/500mA, instead of
the actual 200/1000mA settings. It also initializes other USB power
related GPIOs.
Solves some USB disconnect issues: FS#12990, FS#12956. I am using a
powered USB HUB with no problems (Vusb=5.05V unloaded), but there
are lots of USB disconnects when using the motherboard USB ports
(Vusb=4.91V), this patch solves all my issues.
Actually, it seems that the USB current drain is limited to 1000mA,
when a load peak occurs most USB2 ports deliver more than 500mA, as
current consumption increases the USB voltage decreases, an excesive
voltage drop produces USB disconnections. Limiting USB current drain
to 500mA also limits the voltage drop, preventing subsequent USB
failures.
Anyway, to minimize voltage drop, it is recommended to use quality
cables and preferably connect to USB ports with higher Vusb.
Change-Id: I1b931aa18ec93bfd1214e475a72e42893eff52f6
32b4558511