tty: serial_mctrl_gpio: Fix COMPILE_TEST build for architectures with custom termios.h

This patch fixes COMPILE_TEST build of serial_mctrl_gpio module for
architectures with custom termios.h header.

sparc64:allmodconfig:

In file included from drivers/tty/serial/serial_mctrl_gpio.c:21:0:
include/uapi/asm-generic/termios.h:22:8: error: redefinition of 'struct termio'
./arch/sparc/include/uapi/asm/termbits.h:16:8: note: originally defined here
make[3]: *** [drivers/tty/serial/serial_mctrl_gpio.o] Error 1

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_mctrl_gpio.c

@@ -18,7 +18,7 @@
 #include <linux/err.h>
 #include <linux/device.h>
 #include <linux/gpio/consumer.h>
-#include <uapi/asm-generic/termios.h>
+#include <linux/termios.h>
 
 #include "serial_mctrl_gpio.h"