power: supply: qcom_smbb: Add otg regulator for control of vbus

Add a regulator to control the OTG chargepath switch.  This
is used by USB code to control VBUS direction - out for host mode
on the OTG port, and in for charging mode.

Signed-off-by: Tim Bird <tim.bird@sonymobile.com>
Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
[stephen.boyd@linaro.org: Fix supply name, constify ops, drop
machine.h and of_regulator.h includes]
Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>