[PATCH] n_hdlc.c: remove unused declaration

drivers/char/n_hdlc.c:194: warning: `n_hdlc_tty_room' declared `static' but
never defined

Signed-off-by: Grant Coady <gcoady@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>