dmaengine: ti: k3-udma-private: Use udma_read/write for register access

dmaengine: ti: k3-udma-private: Use udma_read/write for register access

Instead of using higher level wrappers (udma_rchanrt/tchanrt read/write),
use the underlying register access functions directly.

This will allow changes in the higher level wrappers within the DMAengine
driver.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lore.kernel.org/r/20200707102352.28773-5-peter.ujfalusi@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>