Input: fix misspelling of Hangeul key

Fix a mispelling of the korean alphabet name in the input subsystem.
See http://en.wikipedia.org/wiki/Hangeul#Names

 for more details.

KEY_HANGUEL left to not break people

Signed-off-by: Jerome Pinot <ngc891@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>