dma: mxs-dma: make platform_device_id more generic

Rewrite mxs_dma_is_apbh and mxs_dma_is_apbx in order to support
other SoCs like imx6q and reform the platform_device_id for the
better further dt support.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Huang Shijie <b32955@freescale.com>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Vinod Koul <vinod.koul@intel.com>