power: smb135x-charger: workaround for otg enablement

To enable OTG the software has to issue enable, disable and
enable in that order to actually enable the OTG mode. Moreover
each step in this sequence needs to be done withing 10mS of the prior
step.

Update the driver to do so.

Change-Id: Iba619a5400934047b1d874acb2c249a4cb108bdd
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>