[PATCH, AARCH64] support R_AARCH64_NONE as gas input for 64-bit code

[Nick Clifton]

Hi Jim,

> 016-05-09  Jim Wilson  <jim.wilson@linaro.org>
> 
> 	bfd/
> 	* elfnn-aarch64.c: Unconditionally enable R_AARCH64_NULL and
> 	R_AARCH64_NONE.  Use HOWTO64 for R_AARCH64_NULL.
> 	* relocs.c: Add BFD_RELOC_AARCH64_NULL.
> 	* bfd-in2.h: Regenerate.
> 	* libbfd.h: Likewise.

Approved - please apply.

Cheers
  Nick