power_supply: kill android-battery driver

Discontinued in favor of future userspace charging helpers.

Change-Id: I840a94ff42e2219cfd8759f919f6188355a63d92
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Git-commit: b396b36a15b27767215ea6a35174a6dba0302ba1
Git-Repo: https://android.googlesource.com/kernel/common.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>