Frameworks: Fix possible ANR and navigation bar freeze

Big thanks to ralpheboyo which provided us the first time a usable
anr trace where we can see what the actual problem is.

The random ANR is caused due of to much work on the navigationBarCanMove
feature. We call way to often the provider value even though it is only
needed on initiliazing or on update of the value. Currently we call it on every
possible navigation bar change and this multiple times.

To fix it just call it on init and on contentobserver changes and pass
the new value to the navigation bar view and the search panel view

PS:
- remove another call
PS
- add one security check just to be sure
PS
- get one step further and put out the navigation ring config as well
  and reduce it to just one call.

Change-Id: Ica6116289d5bc50e9bedcd34b4b165062fa3468d

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java