staging: gdm72xx: fix interruptible_sleep_on race

interruptible_sleep_on is racy and going away. This replaces the
use in the gdm72xx driver with the appropriate
wait_event_interruptible_lock_irq.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>