[aarch64] Add Qualcomm saphira CPU support.

[aarch64] Add Qualcomm saphira CPU support.

This patch adds an mcpu option for the Qualcomm saphira server part.
Tested on aarch64 and did not find any regressions resulting from this
patch.

2017-11-03  Siddhesh Poyarekar  <siddhesh.poyarekar@linaro.org>
	    Jim Wilson  <jim.wilson@linaro.org>

	* config/aarch64/aarch64-cores.def (saphira): New CPU.
	* config/aarch64/aarch64-tune.md: Regenerated.
	* doc/invoke.texi (AArch64 Options/-mtune): Add "saphira".
	* gcc/config/aarch64/aarch64.c (saphira_tunings): New tuning table.

Co-Authored-By: Jim Wilson <jim.wilson@linaro.org>
From-SVN: r254372