Do not define builtins that overload disabled builtins.

Do not define builtins that overload disabled builtins.

	PR bootstrap/92661
	* config/rs6000/rs6000-c.c (struct altivec_builtin_types): Move to
	rs6000.h.
	(altivec_overloaded_builtins): Move to rs6000-call.c.
	* config/rs6000/rs6000.h (struct altivec_builtin_types): Moved from
	rs6000-c.c.
	* config/rs6000/rs6000-call.c (rs6000_builtin_info): Make static.
	(altivec_overloaded_builtins): Moved from rs6000-c.c.
	(rs6000_common_init_builtins): Do no define builtins that overload
	builtins that have been disabled.

From-SVN: r278973