Adding kuser_helper on note to all arm32 binaries.

A kernel change is going in for 64bit arm to disable kuser_helper vector
pages for 32bit processes.  This change adds a special elf note to
all arm32 binaries built with bionic.  This note tells the kernel to
load the kuser_helper vector page for the process.

Bug: 33689037
Test: Manual - Phone boots, 32bit binaries have the notes, 64bit
binaries do not.
Change-Id: Ib8366e2a0810092b71381d57dee4bdaa56369a24