UBI: allow all ioctls

Some ioctl's in UBI are enabled only when debugging is switched
on. There is not particular reason for this, just noone needed
them. However, some people need the now for their user-space
development. Thus, allow these ioctl's even if UBI debugging
is disabled.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>