[PATCH, BINUTILS, AARCH64, 5/9] Add DC CVADP instruction

[PATCH, BINUTILS, AARCH64, 5/9] Add DC CVADP instruction

This patch is part of the patch series to add support for ARMv8.5-A
extensions.
(https://developer.arm.com/products/architecture/cpu-architecture/a-profile/docs/ddi0596/a/a64-base-instructions-alphabetic-order/dc-data-cache-operation-an-alias-of-sys)

This patch adds the DC CVADP instruction. Since this has a separate
identification mechanism a new feature bit is added.

*** include/ChangeLog ***

2018-10-09  Sudakshina Das  <sudi.das@arm.com>

	* opcode/aarch64.h (AARCH64_FEATURE_CVADP): New.

*** opcodes/ChangeLog ***

2018-10-09  Sudakshina Das  <sudi.das@arm.com>

	* aarch64-opc.c (aarch64_sys_regs_dc): New entry for cvadp.
	(aarch64_sys_ins_reg_supported_p): New check for above.

*** gas/ChangeLog ***

2018-10-09  Sudakshina Das  <sudi.das@arm.com>

	* testsuite/gas/aarch64/sysreg-4.s: Test instruction.
	* testsuite/gas/aarch64/sysreg-4.d: Likewise.
	* testsuite/gas/aarch64/illegal-sysreg-4.l: Likewise.