input: Add workaround for broken hardware keyboard support

* Add workaround var for devices with broken kernels

Change-Id: Ib6ade70f399067469ba5aece48c6ec4608125d75

Conflicts:
	services/java/com/android/server/wm/WindowManagerService.java
input: Fix workaround for broken hardware keyboard support

Using a wrong reference to mHardKeyboardAvailable caused device config
to never report physical keyboards.

Change-Id: I9b64e2d89512436c17fa8929464e2b727fba1cf3