Add processor names to processor_target_table and use it instead of
target_cpu_default and cpu_names.

	PR target/59587
	* config/i386/i386.c (struct ptt): Add a field for processor
	name.
	(processor_target_table): Sync with processor_type.  Add
	processor names.
	(cpu_names): Removed.
	(ix86_option_override_internal): Default x_ix86_tune_string
	to processor_target_table[TARGET_CPU_DEFAULT].name.
	(ix86_function_specific_print): Assert arch and tune <
	PROCESSOR_max.  Use processor_target_table to print arch and
	tune names.
	* config/i386/i386.h (TARGET_CPU_DEFAULT): Default to
	PROCESSOR_GENERIC.
	(target_cpu_default): Removed.
	(processor_type): Reordered.

From-SVN: r206202