battle tent start and create frontier struct in saveblock

src/battle_controller_link_partner.c

@@ -1684,7 +1684,7 @@ static void LinkPartnerHandleCmd55(void)
 {
     sub_81851A8(&gBattleBufferA[gActiveBattler][4]);
     gBattleOutcome = gBattleBufferA[gActiveBattler][1];
-    gSaveBlock2Ptr->field_CA9_b = gBattleBufferA[gActiveBattler][2];
+    gSaveBlock2Ptr->frontier.field_CA9_b = gBattleBufferA[gActiveBattler][2];
     FadeOutMapMusic(5);
     BeginFastPaletteFade(3);
     LinkPartnerBufferExecCompleted();