Hi,
  This adds simple -mcpu=thunderx support.  Right now we use the
schedule model of cortex-a53 but we will submit a schedule model for
ThunderX later on.  Note ThunderX is an AARCH64 only processor so I
created a new file to hold the cost tables for it rather than adding
it to aarch-cost-tables.h.

OK?  Built and tested for aarch64-elf.

Thanks,
Andrew Pinski

PS The corresponding binutils patch is located at
https://sourceware.org/ml/binutils/2014-10/msg00170.html .


ChangeLog:
* doc/invoke.texi (AARCH64/mtune): Document thunderx as an available
option also.
* config/aarch64/aarch64-cost-tables.h: New file.
* config/aarch64/aarch64-cores.def (thunderx): New core.
* config/aarch64/aarch64-tune.md: Regenerate.
* config/aarch64/aarch64.c: Include aarch64-cost-tables.h instead of
config/arm/aarch-cost-tables.h.
(thunderx_regmove_cost): New variable.
(thunderx_tunings): New variable.