tty: amba-pl011: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Russell King <[e-mail]>
Cc: Jiri Slaby <[e-mail]>
Cc: [e-mail]
Signed-off-by: Kees Cook <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/amba-pl011.c

···
  * Every polling, It checks the residue in the dma buffer and transfer
  * data to the tty. Also, last_residue is updated for the next polling.
  */
-static void pl011_dma_rx_poll(unsigned long args)
+static void pl011_dma_rx_poll(struct timer_list *t)
 {
-	struct uart_amba_port *uap = (struct uart_amba_port *)args;
+	struct uart_amba_port *uap = from_timer(uap, t, dmarx.timer);
 	struct tty_port *port = &uap->port.state->port;
 	struct pl011_dmarx_data *dmarx = &uap->dmarx;
 	struct dma_chan *rxchan = uap->dmarx.chan;
···
 			dev_dbg(uap->port.dev, "could not trigger initial "
 				"RX DMA job, fall back to interrupt mode\n");
 		if (uap->dmarx.poll_rate) {
-			init_timer(&(uap->dmarx.timer));
-			uap->dmarx.timer.function = pl011_dma_rx_poll;
-			uap->dmarx.timer.data = (unsigned long)uap;
+			timer_setup(&uap->dmarx.timer, pl011_dma_rx_poll, 0);
 			mod_timer(&uap->dmarx.timer,
 				jiffies +
 				msecs_to_jiffies(uap->dmarx.poll_rate));