Add option to enable/disable navring (2/2)

This will add an option to toggle navigation ring.

If the navigation bar is disabled then a standalone
navigation ring is added.

Change-Id: I4d9c2db0ccd801052d1880c3ff29fb2ab2750bc7
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>