target: zephyr: Update to Zephyr 1.6 API. (#1462)

Zephyr 1.6 switched to "unified kernel API". Old API is supported, but
deprecated and leads to warnings.

JerryScript-DCO-1.0-Signed-off-by: Paul Sokolovsky paul.sokolovsky@linaro.org

targets/zephyr/src/jerry-port.c

@@ -63,13 +63,13 @@ void jerry_port_fatal (jerry_fatal_code_t code)
 /**
  * Implementation of jerry_port_get_current_time.
  *
- * @return current timer's counter value in microseconds
+ * @return current timer's counter value in milliseconds
  */
 double
 jerry_port_get_current_time ()
 {
-  int64_t us = sys_tick_get() * sys_clock_us_per_tick;
-  return (double) us / 1000;
+  int64_t ms = k_uptime_get();
+  return (double) ms;
 } /* jerry_port_get_current_time */
 
 /**