msm: board-8960: Enable PMIC USB OTG switch over current protection

Enable over current protection for the PMIC USB OTG switch so that
power is automatically cut to attached USB devices if they draw
too much current.

The OCP enable delay time of 500 microseconds was chosen so that
it was not possible to trigger an OCP event due to inrush current
on the devices tested.  This value may need tuning for other
board layouts.  In general, a small value implies more safety
against damage in short circuit situations but increases the
likelihood of an OCP false trigger due to inrush current.

Change-Id: I21cffb4e960662172391af6ce26fae57f0dbb998
Signed-off-by: David Collins <collinsd@codeaurora.org>