dt-bindings: mfd: syscon: Add Rockchip RV1126 QoS register

Document dt-bindings for Rockchip RV1126 QoS registers.

Signed-off-by: Jagan Teki <jagan@edgeble.ai>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20220723204335.750095-17-jagan@edgeble.ai