xgate cleanup

xgate cleanup

elf32-xgate.c contains many functions that are only stubs and
elf32-xgate.h contains unused declarations.  While this might be
reasonable for the initial commit of a port with subsequent work
fleshing out the stubs, xgate has only had two minor target specific
patches since the initial commit over six years ago.  The rest of the
changes have been general maintenance work applied to all ELF targets,
and some of this work could have been avoided if the stubs hadn't been
there.  So this patch removes all the stubs.

I've kept the functionality of the old elf32_xgate_add_symbol_hook,
implemented in elf32_xgate_backend_symbol_processing.  Presumably,
that's to set the symbol st_target_internal flag for use in
elf32-m68hc1x.c:elf32_m68hc11_relocate_section.

The empty elf32_xgate_relocate_section meant that xgate had no linker.
Or at least, no linker relocation processing.  Deleting the
elf_backend_relocate_section define means the target will now use the
generic linker reloc processing.  How good that is will depend on the
accuracy of the reloc howtos..

I haven't updated the ld testsuite to xfail tests expected to fail
for generic elf targets.

bfd/
	* elf32-xgate.h: Delete.
	* elf32-xgate.c: Delete unnecessary forward declarations, add two
	that are now needed.
	(xgate_elf_bfd_link_hash_table_create)
	(xgate_elf_bfd_link_hash_table_free)
	(xgate_elf_set_mach_from_flags, struct xgate_scan_param)
	(stub_hash_newfunc, elf32_xgate_add_symbol_hook)
	(elf32_xgate_setup_section_lists, elf32_xgate_size_stubs)
	(elf32_xgate_build_stubs, elf32_xgate_check_relocs)
	(elf32_xgate_relocate_section, _bfd_xgate_elf_set_private_flags)
	(elf32_xgate_post_process_headers): Delete.
	(elf32_xgate_backend_symbol_processing): New function.
	(xgate_elf_ignore_reloc, xgate_elf_special_reloc)
	(_bfd_xgate_elf_print_private_bfd_data): Make static.
	(ELF_TARGET_ID, elf_info_to_howto, elf_backend_check_relocs)
	(elf_backend_relocate_section, elf_backend_object_p)
	(elf_backend_final_write_processing, elf_backend_can_gc_sections)
	(elf_backend_post_process_headers, elf_backend_add_symbol_hook)
	(bfd_elf32_bfd_link_hash_table_create)
	(bfd_elf32_bfd_set_private_flags)
	(xgate_stub_hash_lookup): Don't define.
	(elf_backend_symbol_processing): Define.
	* elf-bfd.h (elf_target_id): Delete XGATE_ELF_DATA.
ld/
	* emulparams/xgateelf.sh (TEMPLATE_NAME) Set to generic.
	(EXTRA_EM_FILE): Set to genelf.