AArch64: Remove ldgv and stgv instructions from Armv8.5-A Memory Tagging Extension.

This patch is part of a series of patches to introduce a few changes to the
Armv8.5-A Memory Tagging Extension. This patch removes the LDGV and STGV
instructions. These instructions needed special infrastructure to support
[base]! style for addressing mode. That is also removed now.

Committed on behalf of Sudakshina Das.

*** gas/ChangeLog ***

	* config/tc-aarch64.c (parse_address_main): Remove support for
	[base]! address expression.
	(parse_operands): Remove support for AARCH64_OPND_ADDR_SIMPLE_2.
	(warn_unpredictable_ldst): Remove support for ldstgv_indexed.
	* testsuite/gas/aarch64/armv8_5-a-memtag.d: Remove tests for ldgv
	and stgv.
	* testsuite/gas/aarch64/armv8_5-a-memtag.s: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.l: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.s: Likewise.

*** include/ChangeLog ***

	* opcode/aarch64.h (enum aarch64_opnd): Remove
	AARCH64_OPND_ADDR_SIMPLE_2.
	(enum aarch64_insn_class): Remove ldstgv_indexed.

*** opcodes/ChangeLog ***

	* aarch64-asm.c (aarch64_ins_addr_simple_2): Remove.
	* aarch64-asm.h (ins_addr_simple_2): Likeiwse.
	* aarch64-dis.c (aarch64_ext_addr_simple_2): Likewise.
	* aarch64-dis.h (ext_addr_simple_2): Likewise.
	* aarch64-opc.c (operand_general_constraint_met_p): Remove
	case for ldstgv_indexed.
	(aarch64_print_operand): Remove case for AARCH64_OPND_ADDR_SIMPLE_2.
	* aarch64-tbl.h (struct aarch64_opcode): Remove ldgv and stgv.
	(AARCH64_OPERANDS): Remove ADDR_SIMPLE_2.
	* aarch64-asm-2.c: Regenerated.
	* aarch64-dis-2.c: Regenerated.
	* aarch64-opc-2.c: Regenerated.

(cherry picked from commit 550fd7bf)