dmaengine: xilinx_dma: Move enum xdma_ip_type to driver file

The enum xdma_ip_type is only used inside the Xilinx DMA driver and not
exported to any consumers (nor should it be). So move it from the global
header to driver file itself.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>