Add support for Android Vector calling convention for AArch64

This modification applies the following Android commit when we have an
Android environment. This is the sole non-renderscript in the Android repo

	commit 9212d4fb30a3ca2f4ee966dd2748c35573d9682c
	Author: Tim Murray <timmurray@google.com>
	Date:   Fri Aug 15 16:00:15 2014 -0700

	    Update vector calling convention for AArch64.

	    bug 16846318

	    Change-Id: I3cfd167758b4bd634d8480ee6ba6bb55d61f82a7

Reviewers: srhines, jyknight

Subscribers: mcrosier, aemerson, rengolin, tberghammer, danalbert, srhines

Differential Revision: http://reviews.llvm.org/D17448

llvm-svn: 261533