tty: fix tty_port_tty_*hangup() kernel-doc

The commit below added a new helper, but omitted to move (and add) the
corressponding kernel-doc. Do it now.

Signed-off-by: "Jiri Slaby (SUSE)" <[e-mail]>
Fixes: 2b5eac0f8c6e ("tty: introduce and use tty_port_tty_vhangup() helper")
Link: https://lore.kernel.org/all/[e-mail]/
Reported-by: Ilpo Järvinen <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/driver-api/tty/tty_port.rst

···
 TTY Helpers
 -----------
 
+.. kernel-doc::  include/linux/tty_port.h
+   :identifiers: tty_port_tty_hangup tty_port_tty_vhangup
 .. kernel-doc::  drivers/tty/tty_port.c
-   :identifiers: tty_port_tty_hangup tty_port_tty_wakeup
-
+   :identifiers: tty_port_tty_wakeup
 
 Modem Signals
 -------------

drivers/tty/tty_port.c

···
 }
 EXPORT_SYMBOL(tty_port_hangup);
 
-/**
- * tty_port_tty_hangup - helper to hang up a tty
- * @port: tty port
- * @check_clocal: hang only ttys with %CLOCAL unset?
- */
 void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async)
 {
 	struct tty_struct *tty = tty_port_tty_get(port);

include/linux/tty_port.h

···
 	return port->count + port->blocked_open;
 }
 
+/**
+ * tty_port_tty_hangup - helper to hang up a tty asynchronously
+ * @port: tty port
+ * @check_clocal: hang only ttys with %CLOCAL unset?
+ */
 static inline void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
 {
 	__tty_port_tty_hangup(port, check_clocal, true);
 }
 
+/**
+ * tty_port_tty_vhangup - helper to hang up a tty synchronously
+ * @port: tty port
+ */
 static inline void tty_port_tty_vhangup(struct tty_port *port)
 {
 	__tty_port_tty_hangup(port, false, false);