Revert "Optimize the fuck out of using checks in machines."

This reverts commit 5649e2c34d.

Conflicts:
	code/game/objects/objs.dm

code/game/objects/items/devices/handtv.dm

@@ -23,6 +23,7 @@
 	if (!target)
 		usr.unset_machine()
 		usr.reset_view(usr)
+		src.in_use = 0
 		return
 	for (var/obj/machinery/camera/C in cameras)
 		if (C.c_tag == target)
@@ -33,8 +34,10 @@
 		usr.client.eye = target
 		usr.set_machine(src)
 		src.current = target
+		src.in_use = 1
 	else
 		usr.unset_machine()
+		src.in_use = 0
 		return
 
 /obj/item/device/handtv/check_eye(var/mob/usr as mob)