[ARM] Build attributes for ARMv8.1-A AdvSIMD

[ARM] Build attributes for ARMv8.1-A AdvSIMD

binutils/
2016-03-04  Matthew Wahab  <matthew.wahab@arm.com>

	* readelf.c (arm_attry_tag_FP_arch): Add "NEON for ARMv8.1".

gas/
2016-03-04  Matthew Wahab  <matthew.wahab@arm.com>

	* config/tc-arm.c (aeabi_set_public_attributes): Emit attribute
	for ARMv8.1 AdvSIMD use.
	* testsuite/gas/arm/attr-march-armv8-a+rdma.d: New.
	* testsuite/gas/arm/attr-march-armv8_1-a+simd.d: New.

Change-Id: I3c356e0681b97df2f9c0dabd7c0fd1b441cc2755