serial/max310x: Remove obsolete #ifset TIOC[SG]RS485

Commit e676253b ("serial/8250: Add support for RS485 IOCTLs") added
references to TIOC[SG]RS48 on 8250_core.c. This change triggered the
need to define them in all the arches that uses tty/serial.

This made #ifdef TIOC[SG]RS48 obsolete.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -880,7 +880,6 @@ static void max310x_set_termios(struct uart_port *port,
 static int max310x_ioctl(struct uart_port *port, unsigned int cmd,
 			 unsigned long arg)
 {
-#if defined(TIOCSRS485) && defined(TIOCGRS485)
 	struct serial_rs485 rs485;
 	unsigned int val;
 
@@ -923,7 +922,6 @@ static int max310x_ioctl(struct uart_port *port, unsigned int cmd,
 	default:
 		break;
 	}
-#endif
 
 	return -ENOIOCTLCMD;
 }