No more $C8

Use OPP_ constants separate from trainer constants since
valid opponents can be all Pokemon and trainers

engine/battle/battle_transitions.asm

@@ -82,7 +82,7 @@ BattleTransitions: ; 709d2 (1c:49d2)
 
 GetBattleTransitionID_WildOrTrainer: ; 709e2 (1c:49e2)
 	ld a, [W_CUROPPONENT]
-	cp $c8
+	cp 200
 	jr nc, .trainer
 	res 0, c
 	ret

engine/battle/core.asm

@@ -1214,7 +1214,7 @@ HandlePlayerBlackOut: ; 3c837 (f:4837)
 	cp LINK_STATE_BATTLING
 	jr z, .notSony1Battle
 	ld a, [W_CUROPPONENT]
-	cp $c8 + SONY1
+	cp OPP_SONY1
 	jr nz, .notSony1Battle
 	coord hl, 0, 0  ; sony 1 battle
 	lb bc, 8, 21
@@ -6861,7 +6861,7 @@ InitBattleCommon: ; 3ef3d (f:6f3d)
 	res 1, [hl]
 	callab InitBattleVariables
 	ld a, [wEnemyMonSpecies2]
-	sub $c8
+	sub 200
 	jp c, InitWildBattle
 	ld [W_TRAINERCLASS], a
 	call GetTrainerInformation

engine/battle/read_trainer_party.asm

@@ -101,7 +101,7 @@ ReadTrainer: ; 39c53 (e:5c53)
 
 ; get trainer class number
 	ld a,[W_CUROPPONENT]
-	sub $C8
+	sub 200
 	ld b,a
 	ld hl,TeamMoves