ARM: dts: rmobile: Enable I2C6 on Porter

Enable I2C6 bus on Porter to access the PMIC , ie. to reset the board.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/arch/arm/dts/r8a7791-porter.dts b/arch/arm/dts/r8a7791-porter.dts
index bc93bb2..0592aa7 100644
--- a/arch/arm/dts/r8a7791-porter.dts
+++ b/arch/arm/dts/r8a7791-porter.dts
@@ -351,6 +351,11 @@
 	};
 };
 
+&i2c6 {
+	status = "okay";
+	clock-frequency = <400000>;
+};
+
 &sata0 {
 	status = "okay";
 };