[AArch64][SVE 04/32] Rename neon_type_el to vector_type_el

[AArch64][SVE 04/32] Rename neon_type_el to vector_type_el

Similar to the previous patch, but this time for the neon_type_el
structure.

gas/
	* config/tc-aarch64.c (neon_type_el): Rename to...
	(vector_type_el): ...this.
	(parse_neon_type_for_operand): Update accordingly.
	(parse_typed_reg): Likewise.
	(aarch64_reg_parse): Likewise.
	(vectype_to_qualifier): Likewise.
	(parse_operands): Likewise.
	(eq_neon_type_el): Likewise.  Rename to...
	(eq_vector_type_el): ...this.
	(parse_neon_reg_list): Update accordingly.