Split the ARM Crypto ISA extensions for AES and SHA1+2 into their own options (+aes...

Split the ARM Crypto ISA extensions for AES and SHA1+2 into their own options (+aes and +sha2).  The reason for the split is because with the introduction of Armv8.4-a the implementation of AES has explicitly been made independent of the implementation of the other crypto extensions.

gas	* config/tc-aarch64.c (aarch64_arch_option_table): Add armv8.4-a.
	(aarch64_features):	Added SM4 and SHA3.

include	* opcode/aarch64.h:
	(AARCH64_FEATURE_V8_4, AARCH64_FEATURE_SM4): New.
	(AARCH64_ARCH_V8_4, AARCH64_FEATURE_SHA3): New.

opcodes	* aarch64-tbl.h
	(aarch64_feature_v8_4, aarch64_feature_crypto_v8_2): New.
	(aarch64_feature_sm4, aarch64_feature_sha3): New.
	(aarch64_feature_fp_16_v8_2): New.
	(ARMV8_4, SHA3, SM4, CRYPTO_V8_2, FP_F16_V8_2): New.
	(V8_4_INSN, CRYPTO_V8_2_INSN): New.
	(SHA3_INSN, SM4_INSN, FP16_V8_2_INSN): New.