dmaengine: imx-sdma: Add multi fifo support

The i.MX SDMA engine can read from / write to multiple successive
hardware FIFO registers, referred to as "Multi FIFO support". This is
needed for the micfil driver and certain configurations of the SAI
driver. This patch adds support for this feature.

The number of FIFOs to read from / write to must be communicated from
the client driver to the SDMA engine. For this the struct
dma_slave_config::peripheral_config field is used.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220414162249.3934543-12-s.hauer@pengutronix.de


Signed-off-by: Mark Brown <broonie@kernel.org>