Fix a minor typo in an exported function documentation
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>