ARM: dts: omap5: add fref_xtal_ck support

The clock is directly sourced from sys_clkin, and provides an external
output clock for (typically) TWL6040 chip.
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/omap54xx-clocks.dtsi

@@ -1179,3 +1179,13 @@ wkupaon_clkctrl: clk@20 {
 		};
 	};
 };
+
+&scm_wkup_pad_conf_clocks {
+	fref_xtal_ck: fref_xtal_ck {
+		#clock-cells = <0>;
+		compatible = "ti,gate-clock";
+		clocks = <&sys_clkin>;
+		ti,bit-shift = <28>;
+		reg = <0x14>;
+	};
+};