Merging r214718:

Merging r214718:
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r214718 | uweigand | 2014-08-04 08:53:40 -0500 (Mon, 04 Aug 2014) | 12 lines

[PowerPC] Swap arguments to vpkuhum/vpkuwum on little-endian

In commit r213915, Bill fixed little-endian usage of vmrgh* and vmrgl*
by swapping the input arguments.  As it turns out, the exact same fix
is also required for the vpkuhum/vpkuwum patterns.

This fixes another regression in llvmpipe when vector support is
enabled.

Reviewed by Bill Schmidt.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@214819 91177308-0d34-0410-b5e6-96231b3b80d8