[FREELDR] Fix wrong segment register at lgdt instruction in amd64.S

Author: iLauncherDev

boot/freeldr/freeldr/arch/realmode/amd64.S

@@ -67,11 +67,7 @@ Msg_LongModeSupported:
     call writestr
 
     /* Load the GDT */
-#ifdef _USE_ML
-    lgdt fword ptr [gdtptr]
-#else
-    lgdt cs:[gdtptr]
-#endif
+    lgdt lXdtPrefix ds:[gdtptr]
 
     /* Build the startup page tables */
     call BuildPageTables