Consolidate ppc64 ld/bfd communication

Consolidate ppc64 ld/bfd communication

Moves assorted variables used to communicate between ld and bfd into
a struct, hooks it into the bfd link_hash_table early, and removes
all other places where such variables were passed piecemeal.

bfd/
	* elf64-ppc.h (struct ppc64_elf_params): Define.
	(ppc64_elf_init_stub_bfd, ppc64_elf_edit_opd, ppc64_elf_tls_setup,
	ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
	ppc64_elf_build_stubs): Update prototype.
	* elf64-ppp.c (struct ppc_link_hash_table): Add params, delete other
	fields now in params.  Adjust code throughout file.
	(ppc64_elf_init_stub_bfd): Delete "abfd" parameter, add "params".
	Save params pointer in htab.
	(ppc64_elf_edit_opd, ppc64_elf_tls_setup,
	ppc64_elf_setup_section_lists, ppc64_elf_size_stubs,
	ppc64_elf_build_stubs): Remove parameters now in "params".
ld/
	* emultemps/ppc64elf.em (params): New static struct replacing
	various other static vars.  Adjust code throughout file.