[AArch64] AArch64 SIMD Builtins Better Type Correctness.

[AArch64] AArch64 SIMD Builtins Better Type Correctness.

gcc/
	* gcc/config/aarch64/aarch64-builtins.c
	(aarch64_simd_itype): Remove.
	(aarch64_simd_builtin_datum): Remove itype, add
	qualifiers pointer.
	(VAR1): Use qualifiers.
	(aarch64_build_scalar_type): New.
	(aarch64_build_vector_type): Likewise.
	(aarch64_build_type): Likewise.
	(aarch64_init_simd_builtins): Refactor, remove special cases,
	consolidate main loop.
	(aarch64_simd_expand_args): Likewise.

From-SVN: r205092