Merging r338569:

Merging r338569:
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r338569 | jvesely | 2018-08-01 17:04:36 +0200 (Wed, 01 Aug 2018) | 5 lines

AMDGPU: Allow fp32-denormals feature for r600 targets

This was accidentally removed in r335942.

Differential Revision: https://reviews.llvm.org/D49934
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_70@339103 91177308-0d34-0410-b5e6-96231b3b80d8