Use pointers to static constant variables for crossbar type and for DMA
offset configuration.

Fixes compiler warnings on 64bit architectures:

drivers/dma/ti-dma-crossbar.c: In function ‘ti_dra7_xbar_probe’:
drivers/dma/ti-dma-crossbar.c:398:21: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  xbar->dma_offset = (u32)match->data;
                     ^
drivers/dma/ti-dma-crossbar.c: In function ‘ti_dma_xbar_probe’:
drivers/dma/ti-dma-crossbar.c:431:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  switch ((u32)match->data) {
          ^
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>