USB force fast charging
-Use base from Chad Froebel <chadfroebel@gmail.com> so we continue to
use the same generic sysfs mechanism

-Referenced franco's git for drivers/usb/otg/msm_otg.c changes
franciscofranco/mako@5a8a4c8

Off by default

Turn on:
echo 1 > /sys/kernel/fast_charge/force_fast_charge

Turn off:
echo 0 > /sys/kernel/fast_charge/force_fast_charge