Revert "Runtime toggle of navbar"

This reverts commit b6a1eb3bd5438906f06a076a7c29d97376638496.

Conflicts:
	packages/SettingsProvider/res/values/defaults.xml
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java

Change-Id: I78bbb5c2ba1f301ab61eb6c4a08257fad9f94e27