rs6000: Rename arrays to remove temporary _x suffix

While we had two sets of built-in infrastructure at once, I added _x as a
suffix to two arrays to disambiguate the old and new versions.  Time to fix
that also.

2021-12-06  Bill Schmidt  <wschmidt@linux.ibm.com>

gcc/
	* config/rs6000/rs6000-c.c (altivec_build_resolved_builtin): Rename
	rs6000_builtin_decls_x to rs6000_builtin_decls.
	(altivec_resolve_overloaded_builtin): Likewise.  Also rename
	rs6000_builtin_info_x to rs6000_builtin_info.
	* config/rs6000/rs6000-call.c (rs6000_invalid_builtin): Rename
	rs6000_builtin_info_x to rs6000_builtin_info.
	(rs6000_builtin_is_supported): Likewise.
	(rs6000_gimple_fold_mma_builtin): Likewise.  Also rename
	rs6000_builtin_decls_x to rs6000_builtin_decls.
	(rs6000_gimple_fold_builtin): Rename rs6000_builtin_info_x to
	rs6000_builtin_info.
	(cpu_expand_builtin): Likewise.
	(rs6000_expand_builtin): Likewise.
	(rs6000_init_builtins): Likewise.  Also rename rs6000_builtin_decls_x
	to rs6000_builtin_decls.
	(rs6000_builtin_decl): Rename rs6000_builtin_decls_x to
	rs6000_builtin_decls.
	* config/rs6000/rs6000-gen-builtins.c (write_decls): In generated code,
	rename rs6000_builtin_decls_x to rs6000_builtin_decls, and rename
	rs6000_builtin_info_x to rs6000_builtin_info.
	(write_bif_static_init): In generated code, rename
	rs6000_builtin_info_x to rs6000_builtin_info.
	(write_init_bif_table): In generated code, rename
	rs6000_builtin_decls_x to rs6000_builtin_decls, and rename
	rs6000_builtin_info_x to rs6000_builtin_info.
	(write_init_ovld_table): In generated code, rename
	rs6000_builtin_decls_x to rs6000_builtin_decls.
	(write_init_file): Likewise.
	* config/rs6000/rs6000.c (rs6000_builtin_vectorized_function):
	Likewise.
	(rs6000_builtin_md_vectorized_function): Likewise.
	(rs6000_builtin_reciprocal): Likewise.
	(add_condition_to_bb): Likewise.
	(rs6000_atomic_assign_expand_fenv): Likewise.