ANDROID: GKI: move abi files to android/

It's good to move the abi files out of the root kernel directory, so
move them to android/ to make it obvious these are add-on things, not
anything that is upstream.

Bug: 155573384
Cc: Matthias Maennich <maennich@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I9f6c2269a1c4e8e4233971adc805cb7584d455f9