[AArch64][SVE 01/32] Remove parse_neon_operand_type

[AArch64][SVE 01/32] Remove parse_neon_operand_type

A false return from parse_neon_operand_type had an overloaded
meaning: either the parsing failed, or there was nothing to parse
(which isn't necessarily an error).  The only caller, parse_typed_reg,
would therefore not consume the suffix if it was invalid but instead
(successfully) parse the register without a suffix.  It would still
leave inst.parsing_error with an error about the invalid suffix.

It seems wrong for a successful parse to leave an error message,
so this patch makes parse_typed_reg return PARSE_FAIL instead.

The patch doesn't seem to make much difference in practice.
Most possible follow-on errors use set_first_error and so the
error about the suffix tended to win despite the successful parse.

gas/
	* config/tc-aarch64.c (parse_neon_operand_type): Delete.
	(parse_typed_reg): Call parse_neon_type_for_operand directly.