[PATCH 6/57][Arm][GAS] Add support for MVE instructions: vst/vld{2,4}

[PATCH 6/57][Arm][GAS] Add support for MVE instructions: vst/vld{2,4}

gas/ChangeLog:
2019-05-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* config/tc-arm.c (enum it_instruction_type): Add MVE_UNPREDICABLE_INSN.
	(BAD_EL_TYPE): New error message.
	(parse_neon_el_struct_list): Adapt to be able to accept MVE variant.
	(parse_address_main): Likewise.
	(group_reloc_type): Add GROUP_MVE.
	(enum operand_parse_code): Add new operands.
	(parse_operands): Handle new operands.
	(M_MNEM_vst20, M_MNEM_vst21, M_MNEM_vst40, M_MNEM_vst41, M_MNEM_vst42,
	 M_MNEM_vst43, M_MNEM_vld20, M_MNEM_vld21, M_MNEM_vld40, M_MNEM_vld41,
	 M_MNEM_vld42, M_MNEM_vld43): New encodings.
	(do_mve_vst_vld): New encoding function.
	(do_neon_ld_st_interleave): Use BAD_EL_TYPE.
	(it_fsm_pre_encode): Handle new it_instruction_type
	(handle_pred_state): Likewise.
	* testsuite/gas/arm/mve-vstld-bad.d: New test.
	* testsuite/gas/arm/mve-vstld-bad.l: New test.
	* testsuite/gas/arm/mve-vstld-bad.s: New test.