added function calls to get session keys from lmic secure element

Author: dhineshkumarmcci

src/lmic/lmic.c

@@ -1550,6 +1550,7 @@ static bit_t processJoinAccept (void) {
     }
 
     LMIC_SecureElement_Error_t seErr;
+    LMIC_SecureElement_Aes128Key_t AppSKey, NwkSKey;
 
     seErr = LMIC_SecureElement_Default_decodeJoinAccept(
         LMIC.frame, dlen,
@@ -1559,6 +1560,12 @@ static bit_t processJoinAccept (void) {
 
     if (seErr != LMIC_SecureElement_Error_OK)
         return processJoinAccept_badframe();
+    
+    LMIC_SecureElement_getAppSKey(&AppSKey, 0);
+    LMIC_SecureElement_getNwkSKey(&NwkSKey, 0);
+
+    memcpy(LMIC.artKey, AppSKey.bytes, sizeof(LMIC.artKey));
+    memcpy(LMIC.nwkKey, NwkSKey.bytes, sizeof(LMIC.nwkKey));
 
     u4_t addr = os_rlsbf4(LMIC.frame+OFF_JA_DEVADDR);
     LMIC.devaddr = addr;