[mips] Fix a typo in the compare patterns for MIPS32r6/MIPS64r6.

Summary: The patterns intended for the SETLE node were actually matching the SETLT node.

Reviewers: atanasyan, sstankovic, vmedic

Reviewed By: vmedic

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6997

llvm-svn: 226171