dmaengine: imx-sdma: add fifo offset/words_per_fifo for sais script

dmaengine: imx-sdma: add fifo offset/words_per_fifo for sais script

Add fifo offset and words_per_fifo for  mcu_2_sai/sai_2_mcu scripts.

fifo offset:
0: no offset between fifos, means all fifos are continuous.
1: means 1 word offset between fifos.
2: means 2 word offset between fifos.
...
n: means n word offset between fifos, n max is 15.

words_per_fifo means how many times of fill/fetch fifo before jump to next
fifo, such as 2 audio channels need to be filled per lane.
0: only one time(audio channel) of fill/fetch per fifo before jump.
1: two times(audio channels) of fill/fetch per fifo before jump.
...
n: means n + 1 times(audio channels) of fill/fetch per fifo before jump.
   n max is 15.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Shengjiu Wang <shengjiu.wang@nxp.com>
(cherry picked from commit b59cc564e30dc789a78ea3abf8ae1920369b5e56)