am 180b2259: am 729c9ff5: am 7754e0ce: Merge "[MIPS64] Modify the default MIPS64 build to MIPS64R6."

* commit '180b22590ddd9582c38eafa12333ec477917ac6c':
  [MIPS64] Modify the default MIPS64 build to MIPS64R6.