feat(stpmic1): add USB OTG regulators

Add regulators boost, pwr_sw1 and pwr_sw2 regulators related to
USB OTG supply BOOST, SW_OTG and SWIN/SWOUT. These regulators are
needed since manipulated during the suspend/resume power sequence
as per FDT description for stm32mp15x-xxx boards from
STMicroelectronics.

Change-Id: I6217de707e49882bd5a9100db43e0d354908800d
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>