The canonical CPU variant for ARM according to config.guess uses a

suffix it seems:

    # ./config.guess
    earmv7hfeb-unknown-netbsd7.99.4

Extend the triple parsing to support this. Avoid running the ARM parser
multiple times because StringSwitch is not lazy.

Reviewers: Renato Golin, Tim Northover

Differential Revision: http://reviews.llvm.org/D7166

llvm-svn: 227085