samples: dac: sam: Add missing pin configuration for sam_v71_xult

DAC pins are not defined for SAM V71(B) Xplained Ultra - this was
causing device initialization to fail. This commit fixes that.

Signed-off-by: Dhanesh S R <sr.dhanesh@protonmail.com>

Author: dhanquna

samples/drivers/dac/boards/sam_v71_xult_samv71q21.overlay

@@ -5,3 +5,17 @@
 		dac-resolution = <12>;
 	};
 };
+
+&dacc{
+	status = "okay";
+	pinctrl-0 = <&dac_default>;
+	pinctrl-names = "default";
+};
+
+&pinctrl{
+	dac_default: dac_default{
+		group1 {
+			pinmux = <PB13X_DACC_DAC0>;
+		};
+	};
+};

samples/drivers/dac/boards/sam_v71_xult_samv71q21b.overlay

@@ -5,3 +5,17 @@
 		dac-resolution = <12>;
 	};
 };
+
+&dacc{
+	status = "okay";
+	pinctrl-0 = <&dac_default>;
+	pinctrl-names = "default";
+};
+
+&pinctrl{
+	dac_default: dac_default{
+		group1 {
+			pinmux = <PB13X_DACC_DAC0>;
+		};
+	};
+};