PR binutils/12467

	PR binutils/12467
	* readelf.c (process_program_headers): Issue a warning if there
	are no program headers but the file header has a non-zero program
	header offset.
	(process_section_headers): Issue a warning if there are no section
	headers but the file header has a non-zero section header offset.
	(process_section_groups): Reword the no section message so that it
	can be distinguished from the one issued by process_section_headers.

	* elf.c (assign_file_positions_for_load_sections): Set the program
	header offset and entry size to zero if there are no program
	headers.