mips64: detect Cavium Octeon II in mips_features

Detect Cavium Octeon II CPU. This is needed as a prerequisite for
successful execution of cavium-octeon2 specific tests.

Patch by Zahid Anwar.

Related to Bugzilla issue 326444.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13782 a5019735-40e9-0310-863c-91ae7b9d1cf9
mips64: modify configure.ac to check for cavium supported toolchain

Modify configure to check if we can pass -march=octeon or -march=octeon2
flags to the compiler. This part is required as it gives us information how
to compile (i.e. whether to compile) tests specific for Cavium Octeon boards.

Patch by Zahid Anwar, with minor modifications.

Related to Bugzilla issue 326444.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13783 a5019735-40e9-0310-863c-91ae7b9d1cf9