same same, bit for bit, except not ;) - Channel request mapping now
depends on a new DMAMUX peripheral, and there's no default preset.
So, before enabling dma channel after its configuration, request
must be configured by :
dmamux_set_dma_channel_request(DMAMUX1, DMA_CHANNELx, request_number_from_datasheet);
b9f183bf1e