Char: cyclades, remove bottom half processing

The work done in bottom half doesn't cost much cpu time (e.g.  tty_hangup
itself schedules its own bottom half), it's possible to do the work in isr
directly and save hence some .text.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>