[ARM 2/5 big.LITTLE] Allow tuning parameters without unique tuning targets.

[ARM 2/5 big.LITTLE] Allow tuning parameters without unique tuning targets.

gcc/
	* config/arm/arm-cores.def: Add new column for TUNE_IDENT.
	* config/arm/genopt.sh: Improve layout.
	* config/arm/arm-tune.md: Regenerate.
	* config/arm/arm-tables.opt: Regenerate.
	* config/arm/arm-opts.h (ARM_CORE): Modify macro for TUNE_IDENT.
	* config/arm/arm.c (ARM_CORE): Modify macro for TUNE_IDENT.
	(arm_option_override): When a CPU is chosen, that should also
	form the tune target.
	* config/arm/arm.h (ARM_CORE): Modify macro for TUNE_IDENT.

From-SVN: r206046