[Patch ARM] Add initial tuning for Cortex-A55 and Cortex-A75

[Patch ARM] Add initial tuning for Cortex-A55 and Cortex-A75

Much like my AArch64 patch a few weeks ago, this patch adds support
for the ARM Cortex-A75 and Cortex-A55 processors through the
-mcpu/-mtune values cortex-a55 and cortex-a75, and an
ARM DynamIQ big.LITTLE configuration of these two processors through
the -mcpu/-mtune value cortex-a75.cortex-a55

Both Cortex-A55 and Cortex-A75 support ARMv8-A with the ARM8.1-A and
ARMv8.2-A extensions. This is reflected in the patch, -mcpu=cortex-a75 is
treated as equivalent to passing -mtune=cortex-a75 -march=armv8.2-a+fp16

gcc/

2017-07-04  James Greenhalgh  <james.greenhalgh@arm.com>

	* config/arm/arm-cpus.in (cortex-a55): New.
	(cortex-a75): Likewise.
	(cortex-a75.cortex-a55): Likewise.
	* config/arm/driver-arm.c (arm_cpu_table): Add cortex-a55 and
	cortex-a75.
	* doc/invoke.texi (-mcpu): Document cortex-a55 and cortex-a75.

	* config/arm/arm-cpu-cdata.h: Regenerate.
	* config/arm/arm-cpu-data.h: Regenerate.
	* config/arm/arm-cpu.h: Regenerate.
	* config/arm/arm-tables.opt: Regenerate.
	* config/arm/arm-tune.md: Regenerate.

From-SVN: r249970