m32r.c: Add support for m32rx processor.

m32r.c: Add support for m32rx processor.

        * m32r.c: Add support for m32rx processor.
        * m32r.h: Ditto.
        * m32r.md: Ditto.
        * t-m32r: Ditto.
        * m32r-protos.h: Add prototypes for m32rx functions.
        * doc/invoke.texi: Document -m32rx option.

Co-Authored-By: Andrew MacLeod <amacleod@redhat.com>
Co-Authored-By: Catherine Moore <clm@redhat.com>
Co-Authored-By: Michael Meissner <meissner@redhat.com>
Co-Authored-By: Nick Clifton <nickc@redhat.com>
Co-Authored-By: Richard Henderson <rth@redhat.com>
From-SVN: r46881