readelf: move file related static vars to filedata

readelf: move file related static vars to filedata

The idea here is to get rid of a lot of file related static vars used
to pass data around, in order to not have stale data about one object
file persisting to the next one.

	* readelf.c (archive_file_offset, archive_file_size, dynamic_addr),
	(dynamic_size, dynamic_nent, dynamic_strings, dynamic_strings_length),
	(num_dynamic_syms, nbuckets, nchains, buckets, chains),
	(ngnubuckets, gnubuckets, gnuchains, mipsxlat, ngnuchains),
	(gnusymidx, dynamic_symbols, dynamic_syminfo, dynamic_syminfo_offset),
	(dynamic_syminfo_nent, program_interpreter, dynamic_info),
	(dynamic_info_DT_GNU_HASH, dynamic_info_DT_MIPS_XHASH, version_info),
	(dynamic_section, symtab_shndx_list, group_count, section_groups),
	(section_headers_groups): Move to struct filedata.  Update use
	throughout file.