staging: android: ion: Remove old platform support

Device specific platform support has been haphazard for Ion. There have
been several independent attempts and there are still objections to
what bindings exist right now. Just remove everything for a fresh start.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>