Remove index from AARCH64_FUSION_PAIR

Remove index from AARCH64_FUSION_PAIR

    Instead of doing an explict index in aarch64-fusion-pairs.def, we
    should have an enum which does the index instead.  This allows
    you to add/remove them without worrying about the order being
    correct and having holes or worry about merge conficts.

    OK? Bootstrapped and tested on aarch64-linux-gnu with no regressions.

    ChangeLog:
    * aarch64-fusion-pairs.def: Remove all index to AARCH64_FUSION_PAIR.
    * config/aarch64/aarch64-protos.h (aarch64_fusion_pairs_index): New enum.
    (aarch64_fusion_pairs): Base the shifted value on the index instead
    Rewrite AARCH64_FUSE_ALL to be based on the end index.
    of the argument to AARCH64_FUSION_PAIR.
    * config/aarch64/aarch64.c: Remove the last argument to AARCH64_FUSION_PAIR.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@227094 138bc75d-0d04-0410-961f-82ee72b054a4