ARM: dts: silk: Enable SCIF_CLK frequency and pins

Add and enable the external crystal for the SCIF_CLK and its pinctrl, to
be used by the Baud Rate Generator for External Clock (BRG) on (H)SCIF.

This increases the range and accuracy of supported baud rates.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Simon Horman <[e-mail]>

arch/arm/boot/dts/r8a7794-silk.dts

···
 };
 
 &pfc {
+	pinctrl-0 = <&scif_clk_pins>;
+	pinctrl-names = "default";
+
 	scif2_pins: serial2 {
 		renesas,groups = "scif2_data";
 		renesas,function = "scif2";
+	};
+
+	scif_clk_pins: scif_clk {
+		renesas,groups = "scif_clk";
+		renesas,function = "scif_clk";
 	};
 
 	ether_pins: ether {
···
 	pinctrl-0 = <&scif2_pins>;
 	pinctrl-names = "default";
 
+	status = "okay";
+};
+
+&scif_clk {
+	clock-frequency = <14745600>;
 	status = "okay";
 };