[BINUTILS, ARM] Add Armv8.5-A to select_arm_features and update macros.

[BINUTILS, ARM] Add Armv8.5-A to select_arm_features and update macros.

This patch addresses the following
1) Adding ARMv8.5-A in select_arm_features.
2) Updating the feature macro so that the new ARM_EXT2_* features for
Armv8.5-A are moved to ARM_AEXT2_V8_5A.

*** opcodes/ChangeLog ***

2018-11-06  Sudakshina Das  <sudi.das@arm.com>

	* arm-dis.c (select_arm_features): Update bfd_mach_arm_8
	with Armv8.5-A. Remove reduntant ARM_EXT2_FP16_FML.

*** include/ChangeLog ***

2018-11-06  Sudakshina Das  <sudi.das@arm.com>

	* opcode/arm.h (ARM_ARCH_V8_5A): Move ARM_EXT2_PREDRES and
	ARM_EXT2_SB to ...
	(ARM_AEXT2_V8_5A): Here.