[gold][aarch64]Patch to add support for TLSLE_MOVW_* relocations

[Cary Coutant]

> 2015-02-10  Jing Yu  <jingyu@google.com>
>
>         * aarch64-reloc.def (TLSLE_MOVW_TPREL_G2, TLSLE_MOVW_TPREL_G1,
>         TLSLE_MOVW_TPREL_G1_NC, TLSLE_MOVW_TPREL_G0, TLSLE_MOVW_TPREL_G0_NC,):
>         New relocation.
>         * aarch64.cc (Target_aarch64::Scan::local): Add cases for new
>         TLSLE_MOVW_* relocations.
>         (Target_aarch64::Scan::global): Likewise.
>         (Target_aarch64::Relocate::relocate): Likewise.
>         (Target_aarch64::Relocate::relocate_tls): Add cases and handlings
>         for new TLSLE_MOVW_* relocations.

This is OK for trunk. Thanks!

-cary