[binutils][aarch64] SVE2 feature extension flags.

[binutils][aarch64] SVE2 feature extension flags.

Include all feature flag macros.

The "sve2" extension that enables the core sve2 instructions.
This also enables the sve extension, since sve is a requirement of sve2.

Extra optional sve2 features are the bitperm, sm4, aes, and sha3 extensions.
These are all given extra feature flags, "bitperm", "sve2-sm4",
"sve2-aes", and "sve2-sha3" respectively.
The sm4, aes, and sha3 extensions are explicitly marked as sve2
extensions to distinguish them from the corresponding NEON extensions.

Rather than continue extending the current feature flag numbers, I used
some bits that have been skipped.

gas/ChangeLog:

2019-05-09  Matthew Malcomson  <matthew.malcomson@arm.com>

	* config/tc-aarch64.c: Add command line architecture feature flags
	"sve2", "sve2-sm4", "sve2-aes", "sve2-sha3", "bitperm".
	* doc/c-aarch64.texi: Document new architecture feature flags.

include/ChangeLog:

2019-05-09  Matthew Malcomson  <matthew.malcomson@arm.com>

	* opcode/aarch64.h (AARCH64_FEATURE_SVE2
	AARCH64_FEATURE_SVE2_AES, AARCH64_FEATURE_SVE2_BITPERM,
	AARCH64_FEATURE_SVE2_SM4, AARCH64_FEATURE_SVE2_SHA3): New
	feature macros.

opcodes/ChangeLog:

2019-05-09  Matthew Malcomson  <matthew.malcomson@arm.com>

	* aarch64-tbl.h
	(aarch64_feature_sve2, aarch64_feature_sve2aes,
	aarch64_feature_sve2sha3, aarch64_feature_sve2sm4,
	aarch64_feature_sve2bitperm): New feature sets.
	(SVE2, SVE2_AES, SVE2_SHA3, SVE2_SM4, SVE2_BITPERM): New macros
	for feature set addresses.
	(SVE2_INSN, SVE2_INSNC, SVE2AES_INSN, SVE2SHA3_INSN,
	SVE2SM4_INSN, SVE2SM4_INSNC, SVE2BITPERM_INSN): New macros.