[PATCH 5/57][Arm][GAS] Add support for MVE instructions: vmull{b,t}

[PATCH 5/57][Arm][GAS] Add support for MVE instructions: vmull{b,t}

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

	* config/tc-arm.c (BAD_MVE_AUTO): New error message.
	(BAD_MVE_SRCDEST): Likewise.
	(mark_feature_used): Diagnose MVE only instructions when in
	auto-detection mode or -march=all.
	(enum operand_parse_code): Define new operand.
	(parse_operands): Handle new operand.
	(M_MNEM_vmullt, M_MNEM_vmullb): New encodings.
	(mve_encode_qqq): New encoding helper function.
	(do_mve_vmull): New encoding function.
	(insns): Handle new instructions.
	* testsuite/gas/arm/mve-vmullbt-bad.d: New test.
	* testsuite/gas/arm/mve-vmullbt-bad.l: New test.
	* testsuite/gas/arm/mve-vmullbt-bad.s: New test.