ANDROID: binder: don't enqueue death notifications to thread todo.

This allows userspace to request death notifications without
having to worry about getting an immediate callback on the same
thread; one scenario where this would be problematic is if the
death recipient handler grabs a lock that was already taken
earlier (eg as part of a nested transaction).

Bug: 23525545
Test: binderLibTest.DeathNotificationThread passes
Change-Id: I955e16306fe3110dacb9a391ffff1bf869249495
Signed-off-by: Martijn Coenen <maco@android.com>
Git-commit: bb74562a7f8398231be20a5c9d36225301a9be31
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Prateek Sood <prsood@codeaurora.org>