Use pointers to static constant variables for eDMA binding
type (legacy vs TPCC).

Fixes the following warning when compiling the driver for 64bit
architectures (x86_64 for example):
drivers/dma/edma.c:2185:16: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
   if (match && (u32)match->data == EDMA_BINDING_TPCC)
                ^
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>