delete seven tty headers

Commit 51c9d654 ("Staging: delete tty
drivers") left seven headers unused: nothing in the tree includes them
anymore. Two of those headers were still exported, but since nothing in
the kernel actually uses the things those two headers provide, that
seems pointless. Delete these seven tty headers too.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>