serial: 8250_port: Remove useless NULL checks

After switching to HR timers for RS485 the NULL checks for the object
inside timer functions become useless.

Remove them to avoid confusion to static analyzers.

Fixes 6e0a5de2136b ("serial: 8250: Use hrtimers for rs485 delays")
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_port.c

@@ -1450,13 +1450,13 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
 	struct uart_8250_em485 *em485;
 	struct uart_8250_port *p;
 	unsigned long flags;
+
 	em485 = container_of(t, struct uart_8250_em485, stop_tx_timer);
 	p = em485->port;
 
 	serial8250_rpm_get(p);
 	spin_lock_irqsave(&p->port.lock, flags);
-	if (em485 &&
-	    em485->active_timer == &em485->stop_tx_timer) {
+	if (em485->active_timer == &em485->stop_tx_timer) {
 		__do_stop_tx_rs485(p);
 		em485->active_timer = NULL;
 	}
@@ -1608,12 +1608,12 @@ static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
 	struct uart_8250_em485 *em485;
 	struct uart_8250_port *p;
 	unsigned long flags;
+
 	em485 = container_of(t, struct uart_8250_em485, start_tx_timer);
 	p = em485->port;
 
 	spin_lock_irqsave(&p->port.lock, flags);
-	if (em485 &&
-	    em485->active_timer == &em485->start_tx_timer) {
+	if (em485->active_timer == &em485->start_tx_timer) {
 		__start_tx(&p->port);
 		em485->active_timer = NULL;
 	}