Bluetooth: mgmt: Remove not needed restriction on add/remove OOB data

Those commands don't send any HCI commands to controller so there is no
need to restrict them to only powered up controller. This also makes
implementation more consistent as already stored remote OOB data
persist power toggle.

Signed-off-by: Szymon Janc <szymon.janc@tieto.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>