[AArch64] Cleanup TLS relocation types which don't go through GOT table

[AArch64] Cleanup TLS relocation types which don't go through GOT table

This patch done two types of cleanup:

  * in aarch64_reloc_got_type and elfNN_aarch64_relocate_section

    We don't need those redundant "case" check, as they can be merged
    with the "default" which just "break".

  * in elfNN_aarch64_gc_sweep_hook and elfNN_aarch64_check_relocs

    All TLS local executable relocations and some local dynamic
    relocations (those calculate module offset) actually don't need GOT
    entry, so remove them from GOT entry counting.

2015-08-18  Jiong Wang  <jiong.wang@arm.com>

bfd/
  * elfnn-aarch64.c (aarch64_reloc_got_type): Delete useless check.
  (elfNN_aarch64_relocate_section): Likewise.
  (elfNN_aarch64_gc_sweep_hook): Likewise.
  (elfNN_aarch64_check_relocs): Likewise.