drivers: sdhc: Add SD host controller driver API

Add api for SD host controller driver. SD host controller driver
supports the following operations:

- reset: reset host controller state
- request: send SD command and data via SDHC
- set_io: set I/O settings (voltage, clocks, etc..) on SDHC
- get_card_present: check for card presence
- execute_tuning: run tuning process for UHS cards
- card_busy: check if SD card bus is busy
- get_host_props: get host controller properties

Signed-off-by: Daniel DeGrasse <[email protected]>

Author: danieldegrasse