This adds a translation layer to make the nrfx driver for the nRF SPIM
(SPI Master with EasyDMA) peripheral accessible via the Zephyr's API.
The shim is provided only for nRF52840 because of a hardware anomaly
present in nRF52832. See Anomaly 58 (SPIM: An additional byte is clocked
out when RXD.MAXCNT = 1) in Errata for this chip.
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
998c79d09b