Remove VBlank check in targets that don't need it (#256)

src/core.c

@@ -609,8 +609,10 @@ void EngineMainLoop(void)
         }
 #endif
 
-        // Wait for vblank to finish
-        while (REG_DISPSTAT & DISPSTAT_VBLANK)
+        // NOTE: If other platforms do V-Sync asynchronously, we may need to incorporate this wait.
+        //
+        // Wait for vblank to finish, we only compute the frame once the new frame started.
+        while (PLATFORM_GBA && (REG_DISPSTAT & DISPSTAT_VBLANK))
             ;
     };
 }