power: qpnp-smbcharger: disable pulse skip during OTG

The charger pulse skip mode can cause drastic dips on VBUS when OTG is
enabled. This dip can cause a glitch in the fuel gauge and lock up the
entire peripheral.
Disable the pulse skip mode before enabling OTG and only reenable it
after OTG is disabled.

CRs-Fixed: 862602
Change-Id: Ifb0df393db4a03020a5753aa5d92dfa796e3bd86
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>