[BINUTILS, AARCH64, 8/8] Add data cache instructions for Memory Tagging Extension

[BINUTILS, AARCH64, 8/8] Add data cache instructions for Memory Tagging Extension

This patch is part of the patch series to add support for ARMv8.5-A
Memory Tagging Extensions which is an optional extension to
ARMv8.5-A and is enabled using the +memtag command line option.

This patch adds all the data cache instructions that are part of this
extension:
- DC IGVAC, Xt
- DC IGSW, Xt
- DC CGSW, Xt
- DC CIGSW, Xt
- DC CGVAC, Xt
- DC CGVAP, Xt
- DC CGVADP, Xt
- DC CIGVAC, Xt
- DC GVA, Xt
- DC IGDVAC, Xt
- DC IGDSW, Xt
- DC CGDSW, Xt
- DC CIGDSW, Xt
- DC CGDVAC, Xt
- DC CGDVAP, Xt
- DC CGDVADP, Xt
- DC CIGDVAC, Xt
- DC GZVA, Xt

*** opcodes/ChangeLog ***

2018-11-12  Sudakshina Das  <sudi.das@arm.com>

	* aarch64-opc.c (aarch64_sys_regs_dc): New entries for
	IGVAC, IGSW, CGSW, CIGSW, CGVAC, CGVAP, CGVADP, CIGVAC, GVA,
	IGDVAC, IGDSW, CGDSW, CIGDSW, CGDVAC, CGDVAP, CGDVADP,
	CIGDVAC and GZVA.
	(aarch64_sys_ins_reg_supported_p): New check for above.

*** gas/ChangeLog ***

2018-11-12  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/gas/aarch64/sysreg-4.s: Test IGVAC, IGSW,
	CGSW, CIGSW, CGVAC, CGVAP, CGVADP, CIGVAC, GVA,
	IGDVAC, IGDSW, CGDSW, CIGDSW, CGDVAC, CGDVAP, CGDVADP,
	CIGDVAC and GZVA with DC.
	* testsuite/gas/aarch64/sysreg-4.d: Likewise.
	* testsuite/gas/aarch64/illegal-sysreg-4.l: Likewise.