Char: cyclades, cy_init error handling

- do not panic if tty_register_driver fails
- handle fail paths properly

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>