[Triple] Stop abusing a class to have only static methods and just use

[Triple] Stop abusing a class to have only static methods and just use
the namespace that we are already using for the enums that are produced
by the parsing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246367 91177308-0d34-0410-b5e6-96231b3b80d8