Merge branch 'feature/sdspi_driver' into 'master'

SD SPI mode driver

This MR adds functionality to support SD cards connected via SPI interface.
Additionally, two bugs are fixed:
- Definition of `SPI_TRANS_MODE_DIOQIO_ADDR` in spi_master driver
- SD card probing frequency was 4000kHz instead of 400kHz as required by the standard

See merge request !727