[mips] Recognise the triple used by Debian for MIPS n32 ABI

Triples like mips64-linux-gnuabin32 are documented in this article:
https://wiki.debian.org/Multiarch/Tuples

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313231 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed