Port mystery_event_script

ld_script.txt

@@ -182,7 +182,7 @@ SECTIONS {
         asm/roulette_util.o(.text);
         asm/cable_car_util.o(.text);
         src/save.o(.text);
-        asm/mystery_event_script.o(.text);
+        src/mystery_event_script.o(.text);
         asm/field_effect_helpers.o(.text);
         asm/battle_anim_sound_tasks.o(.text);
         asm/battle_controller_safari.o(.text);