added a way to power gate the sd card
added a way to power gate the sd card

Tech4Race/nrf5x-base,lab11/nrf5x-base,Tech4Race/nrf5x-base,Tech4Race/nrf5x-base,lab11/nrf5x-base,lab11/nrf5x-base,lab11/nrf5x-base,Tech4Race/nrf5x-base