Staging: gdx724x: gdm_mux: Remove explicit cast

Compiler can typecast variables implicitly so, explicit type cast is not
required and should be removed.
Semantic patch used:

@@
type T;
T e;
identifier x;
@@

* T x = (T)e;
Signed-off-by: Shivani Bhardwaj <shivanib134@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm724x/gdm_mux.c

@@ -222,7 +222,7 @@ static void do_rx(struct work_struct *work)
 	struct mux_dev *mux_dev =
 		container_of(work, struct mux_dev, work_rx.work);
 	struct mux_rx *r;
-	struct rx_cxt *rx = (struct rx_cxt *)&mux_dev->rx;
+	struct rx_cxt *rx = &mux_dev->rx;
 	unsigned long flags;
 	int ret = 0;