[AArch64][ld-testsuite] Select correct linker emulation for ILP32 according to endianess

[Nicholas Clifton]

Hi Jiong,

> 2015-06-17  Jiong Wang  <jiong.wang@arm.com>
>
> ld/testsuite/
>    * ld-aarch64/aarch64-elf.exp (aarch64_choose_ilp32_emul): New
>    function.
>    * ld-aarch64/emit-relocs-28.d: Use aarch64_choose_ilp32_emul to choose
>    emulation mode.

Approved - please apply.

Cheers
   Nick