ARM: dts: logicpd-som-lv: Add fixed 26MHz clock as fck for twl

The board uses 26MHz oscillator for the twl4030 HFCLK. This way we will
not depend on the bootloader to configure the CFG_BOOT:HFCLK_FREQ
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/boot/dts/logicpd-som-lv.dtsi

@@ -35,6 +35,13 @@ hsusb2_phy: hsusb2_phy {
 		reset-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>; /* gpio_4 */
 		#phy-cells = <0>;
 	};
+
+	/* fixed 26MHz oscillator */
+	hfclk_26m: oscillator {
+		#clock-cells = <0>;
+		compatible = "fixed-clock";
+		clock-frequency = <26000000>;
+	};
 };
 
 &gpmc {
@@ -79,6 +86,8 @@ twl: twl@48 {
 		reg = <0x48>;
 		interrupts = <7>; /* SYS_NIRQ cascaded to intc */
 		interrupt-parent = <&intc>;
+		clocks = <&hfclk_26m>;
+		clock-names = "fck";
 		twl_audio: audio {
 			compatible = "ti,twl4030-audio";
 			codec {