add fake counter driver for arch=posix

#include <stdint.h>

#include <time.h>

class Counter {

	private:

		Counter(const Counter &copy);

		uint64_t start_sec, start_nsec;

	public:

		uint64_t value;

		volatile uint8_t overflowed;

		Counter() : overflowed(0) {}

		inline void start() {

			struct timespec ts;

			clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);

			start_sec = ts.tv_sec;

			start_nsec = ts.tv_nsec;

		}

		inline void stop() {

			struct timespec ts;

			clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts);

			value = (ts.tv_sec - start_sec) * 1000000000UL;

			value += ts.tv_nsec - start_nsec;

		}

};

extern Counter counter;

#include "driver/counter.h"

Counter counter;