dma: ti: k3-udma: Add support for native configuration of chan/flow

In absence of Device Manager (DM) services such as at R5 SPL stage,
driver will have to natively setup TCHAN/RCHAN/RFLOW cfg registers.
Existing UDMA driver performed the above mentioned configuration
for UDMA. Add similar configuration for PKTDMA here.

Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Signed-off-by: Chintan Vankar <c-vankar@ti.com>