remove unused function move_ball

ncurses-pong.c

@@ -16,12 +16,6 @@ float ball_y = 0.0;
 float dir_x = +2.0;
 float dir_y = +1.0;
 
-void move_ball(float x, float y) {
-  /* Move ball */
-  ball_x = x;
-  ball_y = y;
-}
-
 void paint_ball() {
   int r, c;
   xy2rc(ball_x, ball_y, &r, &c);