power: qpnp-fg: enable USBID conversions on PMi8996 1.0

On PMi8996 1.0, the charger USBID detection is not connected to any
interrupts. This makes it so that OTG is never enabled because the
software can never detect when an OTG cable is connected.

Fix this by using the fuel gauge USBID detection as a workaround. Since
PMi8996 1.0 defaults to turning off usbid conversions, turn them on
again.

CRs-Fixed: 928421
Change-Id: I46d9dd0b45cb825b998bd6c01b0c91f52454683f
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>