MLK-16224-1: dmaengine: add src_fifo_num and dst_fifo_num in dma_slave_config

MLK-16224-1: dmaengine: add src_fifo_num and dst_fifo_num in dma_slave_config

In order to support multi-fifo sdma script, the audio driver need to send
the fifo number to dma driver through dma_slave_config, so add src_fifo_num
and dst_fifo_num two new variable for struct dma_slave_config.

src_fifo_num: bit 0-7 is the fifo number, bit:8-11 is the fifo offset;
dst_fifo_num: same as src_fifo_num

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Robin Gong<yibin.gong@nxp.com>