Corrected an Imperial Set Combo (#3584)

* Follow up to 87e7e88.
* Should reduce SP required not increase SP required for some skills.
Thanks to @attackjom!

db/re/item_combo_db.txt

@@ -26,7 +26,7 @@
 1428:2115,{ bonus3 bAutoSpellWhenHit,"HP_ASSUMPTIO",2,5; }
 1433:2153,{ bonus2 bSkillAtk,"LG_RAYOFGENESIS",10; bonus2 bSkillAtk,"CR_GRANDCROSS",10; }
 1433:2153:18823,{ bonus2 bSkillAtk,"LG_BANISHINGPOINT",20; bonus2 bSkillAtk,"LG_CANNONSPEAR",20; bonus2 bSkillAtk,"LG_SHIELDPRESS",20; }
-1433:2153:18823:28372,{ bonus2 bSkillUseSP,"LG_BANISHINGPOINT",-15; bonus2 bSkillUseSP,"LG_CANNONSPEAR",-10; bonus2 bSkillUseSP,"CR_GRANDCROSS",-30; bonus2 bSkillUseSP,"LG_SHIELDPRESS",-5; }
+1433:2153:18823:28372,{ bonus2 bSkillUseSP,"LG_BANISHINGPOINT",15; bonus2 bSkillUseSP,"LG_CANNONSPEAR",10; bonus2 bSkillUseSP,"CR_GRANDCROSS",30; bonus2 bSkillUseSP,"LG_SHIELDPRESS",5; }
 1433:28372,{ .@r = getequiprefinerycnt(EQI_HAND_R)/2*7; bonus2 bSkillAtk,"LG_CANNONSPEAR",.@r; bonus2 bSkillAtk,"LG_BANISHINGPOINT",.@r; }
 1472:2677,{ bonus bMatkRate,6; bonus bDex,2; bonus bVariableCastrate,-getequiprefinerycnt(EQI_HEAD_TOP); }
 1472:2711,{ bonus bMatkRate,6; bonus bDex,2; bonus bVariableCastrate,-getequiprefinerycnt(EQI_HAND_R); }