serial: mxs: fix buffer overflow

SMATCH correctly found an off-by-one error:

drivers/tty/serial/mxs-auart.c:889 auart_console_write() error: buffer overflow 'auart_port' 5 <= 5

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/mxs-auart.c

@@ -883,7 +883,7 @@ auart_console_write(struct console *co, const char *str, unsigned int count)
 	unsigned int old_ctrl0, old_ctrl2;
 	unsigned int to = 1000;
 
-	if (co->index >	MXS_AUART_PORTS || co->index < 0)
+	if (co->index >= MXS_AUART_PORTS || co->index < 0)
 		return;
 
 	s = auart_port[co->index];