power: qcom-charger: add OTG workaround for PM660

PM660 support configurable delay for softstart done with
minimum value of 3msec and thus OTG can be configured to
a minimum value till softstart completes. Add a PM660
specific workaround to set OTG current limit to 250mA before
enabling OTG mode and reconfigure the current back to desired
value once OTG softstart completes.

CRs-Fixed: 2016131
Change-Id: Iabb9e1c55cc59453825795e045d7fcc6caf8f33e
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>