mips32: small cleanup in show_hwcaps_mips32

Small cleanup in show_hwcaps_mips32(). More will follow as we need to add
support for Cavium boards too.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2763 8f6e269a-dfd6-0310-a8e1-e2731360e62c