arm_acle: Implement data processing intrinsics

Summary:
ACLE 2.0 section 9.2 defines the following "miscellaneous data processing intrinsics": `__clz`, `__cls`, `__ror`, `__rev`, `__rev16`, `__revsh` and `__rbit`.

`__clz` has already been implemented in the arm_acle.h header file. The rest are not supported yet. This patch completes ACLE data processing intrinsics.

Reviewers: t.p.northover, rengolin

Reviewed By: rengolin

Subscribers: aemerson, mroth, llvm-commits

Differential Revision: http://reviews.llvm.org/D4983