Adding a wait before the wakeup signal.

As a precautionary measure sanity check the current sensor mode.  If
needed reset it to "dual".

When the device is responding poorly and needs the wakeup call, it was
missing it.  Giving it a chance to settle first improves the chances
that signal gets through.
Signed-off-by: NRafi Rubin <rafi@seas.upenn.edu>
Tested-by: NPeter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>