tier1: change it to actually be tier1

Author: RaphaelIT7

tier1/premake5_create_project.lua

@@ -127,8 +127,8 @@ group("SourceSDK")
 			["Header files/*"] = {"../public/tier1/*.h", "../public/*.h", "../common/xbox/*.h"}
 		})
 
-		if TIER0_PROJECTCALLBACK then
-			TIER0_PROJECTCALLBACK()
+		if TIER1_PROJECTCALLBACK then
+			TIER1_PROJECTCALLBACK()
 		end
 
 		IncludeSDKCommonInternal()