dmaengine: at_hdmac: platform data move to use .id_table

We remove the use of platform data from DMA controller driver.
We now use of .id_table to distinguish between compatible
types. The two implementations allow to determine the
number of channels and the capabilities of the controller.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>