[Feature][T8TSK-88][System]Develop API and AT to restart modem

Change-Id: I90659afd935827bf25940b2ac460f5a51cdee9fa
diff --git a/lib/liblynq-sim/include/lynq_sim.h b/lib/liblynq-sim/include/lynq_sim.h
index 923d03b..1ebec79 100755
--- a/lib/liblynq-sim/include/lynq_sim.h
+++ b/lib/liblynq-sim/include/lynq_sim.h
@@ -72,6 +72,11 @@
  */
 int lynq_sim_power(int mode);
 
+/**
+ * @brief reset modem
+ * 
+ */
+int lynq_reset_modem(void);
 
 
 #ifdef __cplusplus