cris: fix a build error in drivers/tty/serial/crisv10.c

Fix these errors:

    drivers/tty/serial/crisv10.c:4453: error: 'if_ser0' undeclared (first use in this function): 2 errors in 2 logs
    drivers/tty/serial/crisv10.c:4453: error: (Each undeclared identifier is reported only once: 2 errors in 2 logs
    drivers/tty/serial/crisv10.c:4453: error: for each function it appears in.): 2 errors in 2 logs

"if_ser0" is a typo, it should be "if_serial_0".
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/tty/serial/crisv10.c

@@ -4450,7 +4450,7 @@ static int __init rs_init(void)
 
 #if defined(CONFIG_ETRAX_RS485)
 #if defined(CONFIG_ETRAX_RS485_ON_PA)
-	if (cris_io_interface_allocate_pins(if_ser0, 'a', rs485_pa_bit,
+	if (cris_io_interface_allocate_pins(if_serial_0, 'a', rs485_pa_bit,
 			rs485_pa_bit)) {
 		printk(KERN_CRIT "ETRAX100LX serial: Could not allocate "
 			"RS485 pin\n");
@@ -4459,7 +4459,7 @@ static int __init rs_init(void)
 	}
 #endif
 #if defined(CONFIG_ETRAX_RS485_ON_PORT_G)
-	if (cris_io_interface_allocate_pins(if_ser0, 'g', rs485_pa_bit,
+	if (cris_io_interface_allocate_pins(if_serial_0, 'g', rs485_pa_bit,
 			rs485_port_g_bit)) {
 		printk(KERN_CRIT "ETRAX100LX serial: Could not allocate "
 			"RS485 pin\n");