Do not allow the navigation bar to move if width == height

If width == height and mNavigationBarCanMove is true, the navigation bar
doesn't shows properly. Because wm doesn't know if the device is in landscape
mode or portrait mode.

Change-Id: I2077eacae50e6e498767f5c93b697e0459ad07fe
Signed-off-by: Devin Kim <dojip.kim@lge.com>