Fix mips segfault on GOT access of absolute symbol

When a symbol is absolute, this code in mips_elf_record_got_page_entry
      entry = bfd_zalloc (sec->owner, sizeof (*entry));
segfaults.  sec == bfd_abs_section_ptr and sec->owner == NULL.

	* elfxx-mips.c (mips_elf_record_got_page_entry): Pass in a
	mips_elf_traverse_got_arg* rather than mips_got_info*.
	Adjust caller.  Alloc on output_bfd rather than symbol section
	owner.