spi_slave_get_trans_result() function

Get the result of a SPI transaction queued earlier This routine will wait until a transaction to the given device (queued earlier with spi_slave_queue_trans) has successfully completed. It will then return the description of the completed transaction so software can inspect the result and e.g. free the memory or reuse the buffers. It is mandatory to eventually use this function for any transaction queued by ``spi_slave_queue_trans``.