Add support for Android Vector calling convention for AArch64

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