De-duplicate vertical moving platform fix for player/SCM

Instead of having two separate functions to move entities along vertical
moving platforms, one for the player and one for the supercrewmate, they
have been consolidated into one function.

desktop_version/src/Entity.h

@@ -152,9 +152,7 @@ public:
 
     void entitymapcollision(int t);
 
-    void movingplatformfix(int t);
-
-    void scmmovingplatformfix(int t);
+    void movingplatformfix(int t, int j);
 
     void hormovingplatformfix(int t);