power: smb138x-charger: increase OTG concurrent mode threshold

OTG voltage is on the lower end of the spec and the OTG device may not
function properly. Increase the concurrent mode threshold in order to
raise the OTG voltage level to better support OTG devices.

Change-Id: I5eb952d67332b3f48d7f59e8329c30a0822a1c7e
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>