power: smb1360: Update the OTG regulator name for SMB1360

Update the OTG regulator name to 'qcom,smb1360-vbus' to 
match the name used while defining the regulator in DT.

Change-Id: Ic19b543c45d57ba0c6adb07932c0ca5787e90ff9
Signed-off-by: Sundara Vinayagam <sundvi@codeaurora.org>