powerpc: dts: p2020: Add serial0 and serial1 via pq3-duart-0.dtsi

Import pq3-duart-0.dtsi device tree include file from upstream Linux kernel
for P2020. This allows U-Boot to use P2020 device tree files from upstream
Linux kernel which reference serial0 or serial1 devices.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/arch/powerpc/dts/p2020-post.dtsi b/arch/powerpc/dts/p2020-post.dtsi
index 6d46f7d..8d30fa2 100644
--- a/arch/powerpc/dts/p2020-post.dtsi
+++ b/arch/powerpc/dts/p2020-post.dtsi
@@ -49,6 +49,7 @@
 
 /include/ "pq3-i2c-0.dtsi"
 /include/ "pq3-i2c-1.dtsi"
+/include/ "pq3-duart-0.dtsi"
 
 /include/ "pq3-etsec1-0.dtsi"
 /include/ "pq3-etsec1-1.dtsi"