Don't use BFD_TRADITIONAL_FORMAT flag in COFF support

info->traditional_format is available, or can be easily made
available.  This relegates BFD_TRADITIONAL_FORMAT to AOUT use only.

	* coff-rs6000.c (_bfd_xcoff_put_symbol_name): Replace abfd param
	with info param.  Test info->traditional_format rather than
	BFD_TRADITIONAL_FORMAT flag.
	* coff64-rs6000.c (_bfd_xcoff64_put_symbol_name): Likewise.
	* libxcoff.h (struct xcoff_backend_data_rec): Update
	_xcoff_put_symbol_name prototype.
	(bfd_xcoff_put_symbol_name): Add info param.
	* xcofflink.c (xcoff_find_tc0): Update bfd_xcoff_put_symbol_name call.
	(xcoff_write_global_symbol): Likewise.
	(xcoff_link_input_bfd): Test info->traditional_format rather than
	BFD_TRADITIONAL_FORMAT flag.
	* cofflink.c (_bfd_coff_final_link): Likewise.
	(_bfd_coff_link_input_bfd, _bfd_coff_write_global_sym): Likewise.