tty: Correct inline types for tty_driver_kref_get()

tty_driver_kref_get() should be static inline and not extern inline
(the latter even changed it's semantics in gcc >= 4.3).

Signed-off-by: Adrian Bunk <[e-mail]>
Signed-off-by: Alan Cox <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/tty_driver.h

···
 extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
 
 extern void tty_driver_kref_put(struct tty_driver *driver);
-extern inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
+
+static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
 {
 	kref_get(&d->kref);
 	return d;