Get rid of common syms (#2040)

src/battle_tower.c

@@ -45,7 +45,7 @@ EWRAM_DATA const struct BattleFrontierTrainer *gFacilityTrainers = NULL;
 EWRAM_DATA const struct FacilityMon *gFacilityTrainerMons = NULL;
 
 // IWRAM common
-u16 gFrontierTempParty[MAX_FRONTIER_PARTY_SIZE];
+COMMON_DATA u16 gFrontierTempParty[MAX_FRONTIER_PARTY_SIZE] = {0};
 
 // This file's functions.
 static void InitTowerChallenge(void);