board: MCR3000: migrate to DM_SERIAL

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
diff --git a/arch/powerpc/dts/mcr3000.dts b/arch/powerpc/dts/mcr3000.dts
index ef423d7..5abf111 100644
--- a/arch/powerpc/dts/mcr3000.dts
+++ b/arch/powerpc/dts/mcr3000.dts
@@ -12,4 +12,11 @@
 	WDT: watchdog@0 {
 		compatible = "fsl,pq1-wdt";
 	};
+	SERIAL: smc@0 {
+		compatible = "fsl,pq1-smc";
+	};
+
+	chosen {
+		stdout-path = &SERIAL;
+	};
 };
diff --git a/configs/MCR3000_defconfig b/configs/MCR3000_defconfig
index 2e79425..33c6073 100644
--- a/configs/MCR3000_defconfig
+++ b/configs/MCR3000_defconfig
@@ -79,3 +79,4 @@
 CONFIG_DEFAULT_DEVICE_TREE="mcr3000"
 CONFIG_WDT=y
 CONFIG_WDT_MPC8xx=y
+CONFIG_DM_SERIAL=y