variants: Add native_posix variant support

Add support for native_posix in limited capacity

Signed-off-by: Dhruva Gole <goledhruva@gmail.com>

Author: DhruvaG2000

variants/native_posix/native_posix.overlay

@@ -0,0 +1,7 @@
+/ {
+	zephyr,user {
+		digital-pin-gpios = <&gpio0 0 0>;
+		serial = <&uart0>;
+		i2cs = <&i2c0>;
+	};
+};

variants/native_posix/native_posix_pinmap.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2022 Dhruva Gole
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/* All the pins that are 100 + x are gpio1 pins and < 100 are in gpio0 */
+#pragma once
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+

variants/variants.h

@@ -23,6 +23,9 @@
 #ifdef CONFIG_BOARD_CC3220SF_LAUNCHXL
 #include "cc3220sf_launchxl_pinmap.h"
 #endif // CONFIG_BOARD_CC3220SF_LAUNCHXL
+#ifdef CONFIG_BOARD_NATIVE_POSIX
+#include "native_posix_pinmap.h"
+#endif // CONFIG_BOARD_NATIVE_POSIX
 
 #define DIGITAL_PIN_EXISTS(n, p, i, dev, num)                                                      \
 	(((dev == DT_REG_ADDR(DT_PHANDLE_BY_IDX(n, p, i))) &&                                      \