dma: ti: k3-udma: Fix debug prints during enabling MEM_TO_DEV transfers

Fix up the debug prints that were dumping state of TCHAN RT registers to
use tchan for MEM_TO_DEV transfers.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>