void ctl_spi_deselect_device(CTL_SPI_DEVICE_t *self);
ctl_spi_deselect_device deselects the device self on the bus that it is attached to. To do this, the device's select method is invoked with a non-zero state, and releases the lock on the SPI bus.
Deselecting a deselected device acts as a no-operation.