[Arm, 3/3] Add Execution and Data Prediction instructions for AArch32

[Arm, 3/3] Add Execution and Data Prediction instructions for AArch32

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/exploration-tools)

This patch adds the Execution and Data Prediction Restriction
instructions (that is, cfprctx, dvprxtc, cpprctx). These are all
aliases to MCR and are disassembled as such.

This instruction is retrospectively made optional for all versions of
the architecture from ARMv8.0 to ARMv8.4 and is mandatory from
ARMv8.5.  Hence adding a new +predres for older versions of the
architecture.

*** include/ChangeLog ***

2018-10-05  Sudakshina Das  <sudi.das@arm.com>

	* opcode/arm.h (ARM_EXT2_PREDRES): New.
	(ARM_ARCH_V8_5A): Add ARM_EXT2_PREDRES by default.

*** gas/ChangeLog ***

2018-10-05  Sudakshina Das  <sudi.das@arm.com>

	* config/tc-arm.c (arm_ext_predres): New.
	(insns): Add new cfprctx, dvprctx and cpprctx instructions.
	(arm_extensions): Add "predres".
	* doc/c-arm.texi: Document the above.
	* testsuite/gas/arm/predres-bad.d: New test.
	* testsuite/gas/arm/predres-bad.l: New test.
	* testsuite/gas/arm/predres.s: New test.
	* testsuite/gas/arm/predres1.d: New test.
	* testsuite/gas/arm/predres2.d: New test.