New option falkor for Qualcomm server part

This adds an option for the Qualcomm falkor core, the corresponding
gcc patch is here:

https://gcc.gnu.org/ml/gcc-patches/2016-11/msg00262.html

This was tested with aarch64 and armhf builds and make check and also
by building and running SPEC2006.

        * config/tc-aarch64.c (aarch64_cpus): Add falkor.
        * config/tc-arm.c (arm_cpus): Likewise.
        * doc/c-aarch64.texi: Likewise.
        * doc/c-arm.texi: Likewise.