Orientation aware volume buttons: circumvent the need for idc file

To address the concern about the need to add (to too many device
repos) an idc file with "keyboard.orientationAware = 1" for the
built-in keyboard device that provides the volume buttons:

Regard the keyboard devices as orientation aware by default unless
they are external (USB/bluetooth) or explicitly specified as not
orientation aware by an idc file.

Change-Id: Ib7b5faf305b8c03b7ed568fc51a46423e6d670fe