[user_interface] IC3 VIO and VBUS
change VIO to 1.8V (see note in fpga-bank-87-88 about moving UART-PL_TXD/RXD and UART_TXD/RXD to 1V8 banks)
add resistor divider for VBUS to make sure it does not exceed 3.6V when the board is not powered, see page 20 of CP2105 datasheet. https://www.silabs.com/documents/public/data-sheets/CP2105.pdf