ARM: dts: r8a7742-iwg21d-q7: Enable SCIFB2 node

Enable SCIFB2 interface on iWave RZ/G1H carrier board.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Link: https://lore.kernel.org/r/1590420129-7531-2-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm/boot/dts/r8a7742-iwg21d-q7.dts

@@ -14,6 +14,7 @@ / {
 
 	aliases {
 		serial2 = &scifa2;
+		serial4 = &scifb2;
 	};
 
 	chosen {
@@ -27,6 +28,11 @@ scifa2_pins: scifa2 {
 		groups = "scifa2_data_c";
 		function = "scifa2";
 	};
+
+	scifb2_pins: scifb2 {
+		groups = "scifb2_data", "scifb2_ctrl";
+		function = "scifb2";
+	};
 };
 
 &scifa2 {
@@ -35,3 +41,11 @@ &scifa2 {
 
 	status = "okay";
 };
+
+&scifb2 {
+	pinctrl-0 = <&scifb2_pins>;
+	pinctrl-names = "default";
+
+	uart-has-rtscts;
+	status = "okay";
+};