power: smb135x-charger: apply OTG workaround for v2 chip only

Currently, the OTG workaround is applied to each different version of SMB
chip. However, this workaround is needed only for v2 chip. Hence update
the driver accrodingly.

Change-Id: Icc71f0509703ae74ba0156205b775a51ce604225
CRs-fixed: 699400
Signed-off-by: Ke Liu <keliu@codeaurora.org>