dmaengine: imx-sdma: use platform_device_id to identify sdma version

dmaengine: imx-sdma: use platform_device_id to identify sdma version

It might be not good to use software defined version to identify sdma
device type, when hardware does not define such version.  Instead,
soc name is stable enough to define the device type.

The patch uses platform_device_id rather than version number passed
by platform data to identify sdma device type/version.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Vinod Koul <vinod.koul@intel.com>