boards: esp32c6_devkitc: Add CAN sample

Add CAN sample for esp32c6_devkitc.

Signed-off-by: Raffael Rostagno <raffael.rostagno@espressif.com>

Author: Raffael Rostagno

tests/drivers/can/api/boards/esp32c6_devkitc_hpcore.overlay

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* Enable CAN bus */
+&twai0 {
+	status = "okay";
+	pinctrl-0 = <&twai_default>;
+	pinctrl-names = "default";
+
+	can-transceiver {
+		max-bitrate = <1000000>;
+	};
+};
+
+&pinctrl {
+	twai_default: twai_default {
+		group1 {
+			pinmux = <TWAI0_RX_GPIO5>;
+			output-enable;	/* enable internal loopback */
+		};
+		group2 {
+			pinmux = <TWAI0_TX_GPIO5>;
+			input-enable;	/* enable internal loopback */
+		};
+	};
+};