Merging r259059:

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r259059 | thomas.stellard | 2016-01-28 09:13:44 -0800 (Thu, 28 Jan 2016) | 14 lines

AMDGPU: waitcnt operand fixes

Summary:
Allow lgkmcnt up to 0xF (hardware allows that).
Fix mask for ExpCnt in AMDGPUInstPrinter.

Reviewers: tstellarAMD, arsenm

Subscribers: arsenm

Differential Revision: http://reviews.llvm.org/D16314

Patch by: Nikolay Haustov

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llvm-svn: 271590