dmaengine: imx: Move header to include/dma/

The i.MX DMA drivers are device tree only, nothing in
include/linux/platform_data/dma-imx.h has platform_data in it, so move
the file to include/linux/dma/imx-dma.h.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-By: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20220414162249.3934543-10-s.hauer@pengutronix.de


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