Rename PowerPC64 pcrel GOT TLS relocations

Rename PowerPC64 pcrel GOT TLS relocations

These relocations should have had REL in their names, to reflect the
fact that they are pc-relative.  Fix that now by adding _PCREL.
I've added some back-compatibility code to support anyone using
.reloc with the old relocations.

include/
	* elf/ppc64.h (elf_ppc64_reloc_type): Rename
	R_PPC64_GOT_TLSGD34 to R_PPC64_GOT_TLSGD_PCREL34,
	R_PPC64_GOT_TLSLD34 to R_PPC64_GOT_TLSLD_PCREL34,
	R_PPC64_GOT_TPREL34 to R_PPC64_GOT_TPREL_PCREL34, and
	R_PPC64_GOT_DTPREL34 to R_PPC64_GOT_DTPREL_PCREL34.
bfd/
	* reloc.c: Rename
	BFD_RELOC_PPC64_GOT_TLSGD34 to BFD_RELOC_PPC64_GOT_TLSGD_PCREL34,
	BFD_RELOC_PPC64_GOT_TLSLD34 to BFD_RELOC_PPC64_GOT_TLSLD_PCREL34,
	BFD_RELOC_PPC64_GOT_TPREL34 to BFD_RELOC_PPC64_GOT_TPREL_PCREL34,
	BFD_RELOC_PPC64_GOT_DTPREL34 to BFD_RELOC_PPC64_GOT_DTPREL_PCREL34.
	* elf64-ppc.c: Update throughout for reloc renaming.
	(ppc64_elf_reloc_name_lookup): Handle old reloc names.
	* libbfd.h: Regenerate.
	* bfd-in2.h: Regenerate.
gas/
	* config/tc-ppc.c: Update throughout for reloc renaming.
elfcpp/
	* powerpc.h: Rename
	R_PPC64_GOT_TLSGD34 to R_PPC64_GOT_TLSGD_PCREL34,
	R_PPC64_GOT_TLSLD34 to R_PPC64_GOT_TLSLD_PCREL34,
	R_PPC64_GOT_TPREL34 to R_PPC64_GOT_TPREL_PCREL34, and
	R_PPC64_GOT_DTPREL34 to R_PPC64_GOT_DTPREL_PCREL34.
gold/
	* powerpc.cc: Update throughout for reloc renaming.