[ARM] Support ARMv8.2 RAS extension.

[ARM] Support ARMv8.2 RAS extension.

The ARMv8.2 architecture includes the RAS extension which adds an
instruction, ESB, and a number of coprocessor registers. This patch adds
the instruction to binutils, making it available when -march=armv8.2-a
is selected. It also adds tests for the instruction and for the
coprocessor registers.

gas/
2016-01-12  Matthew Wahab  <matthew.wahab@arm.com>

	* config/tc-arm.c (arm_ext_v8_2): New.
	(insns): Add "esb".
	* testsuite/gas/arm/armv8_2-a.d: New.
	* testsuite/gas/arm/armv8_2-a.s: New.

opcodes/
2016-01-12  Matthew Wahab  <matthew.wahab@arm.com>

	* arm-dis.c (arm_opcodes): Add "esb".
	(thumb_opcodes): Likewise.

Change-Id: I67f3d70789db78d1c66a56c4994675f99ac15e34