arm: mach-k3: am62p: Add QoS support for DSS

arm: mach-k3: am62p: Add QoS support for DSS

Enable Quality of Service (QoS) blocks for Display SubSystem (DSS), by
servicing the DSS - DDR traffic from the Real-Time (RT) queue. This is
done by setting the DSS DMA orderID to greater than 7.

DDR intensive software applications can overwhelm the DSS's access to
the DDR because of their higher frequency DDR accesses. This can cause
flickering in display with certain applications running parallely if
the DSS traffic is being serviced through non-RT queue.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>