power: smb135x: smb1351: avail of simpler regulator registration api

Change,
a0c7b164 regulator: of: Provide simplified DT parsing method
enables to register a regulator without constructing an regulator_init_data
structure. The regulator_init_data is instantiated within the
registration api and is filled with information by parsing the regualtor
device node.

Avail of this convenience while registering OTG regulators in the
smb135x and smb1351 drivers.

Change-Id: I2eb2866f9941db797ede1676e92bb87b4a23c925
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>