UPSTREAM: binder: fix handling of misaligned binder object

Fixes crash found by syzbot:
kernel BUG at drivers/android/binder_alloc.c:LINE! (2)

(cherry pick from commit 26528be6720bb40bc8844e97ee73a37e530e9c5e)
Bug: 67668716
Reported-and-tested-by:  <syzbot+55de1eb4975dec156d8f@syzkaller.appspotmail.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: Ib8597dd05a158f78503d4affe6c5f46ded16a811