[AArch64] Fix feature dependencies for +simd and +crypto

[AArch64] Fix feature dependencies for +simd and +crypto

According to the gas manual, +simd implies +fp and +crypto implies +simd.
Make sure +nofp turns +simd, +crypto and +fp16 off.

gas/
2016-11-07  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config/tc-aarch64.c (aarch64_features): Fix "simd" and "crypto".
	* testsuite/gas/aarch64/illegal-crypto-nofp.d: New.
	* testsuite/gas/aarch64/illegal-crypto-nofp.l: New.
	* testsuite/gas/aarch64/illegal-fp16-nofp.d: New.
	* testsuite/gas/aarch64/illegal-fp16-nofp.l: New.
	* testsuite/gas/aarch64/illegal-fp16-nofp.s: New.