dev: add functions to create device objects

dev/bus.c

@@ -0,0 +1,12 @@
+#include <socks/device.h>
+
+struct bus_device *bus_device_create(void)
+{
+	struct device *dev = device_alloc();
+	if (!dev) {
+		return NULL;
+	}
+
+	dev->dev_type = DEV_TYPE_BUS;
+	return BUS_DEVICE(dev);
+}