Char: genrtc, use wait_event_interruptible

genrtc, use wait_event_interruptible

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>