* target.h (struct target_section): Delete member bfd.
All users updated to use the_bfd_section->owner instead.
* exec.c (add_to_section_table): Assert bfd is expected value.
Remove initialization of target_section.bfd.
(remove_target_sections): Update.
(section_table_available_memory): Update.
(section_table_xfer_memory_partial): Update.
(print_section_info): Update.
(exec_set_section_address): Update.
* record-full.c (record_full_core_xfer_partial): Update.
* solib-svr4.c (svr4_relocate_section_addresses): Update.
* solib-target.c (solib_target_relocate_section_addresses): Update.
* symfile.c (build_section_addr_info_from_section_table): Update.
* target.c (memory_xfer_live_readonly_partial): Update.
(memory_xfer_partial_1): Update.