usb-serial: remove NULL check

Julia Lawell found a case where a NULL check was misplaced in the
usb-serial code. However as the object in question cannot be NULL the
check can simply be removed.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 080ade2..cfcfd5a 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -511,9 +511,6 @@
 
 	dbg("%s - port %d", __func__, port->number);
 
-	if (!port)
-		return;
-
 	tty = tty_port_tty_get(&port->port);
 	if (!tty)
 		return;