Correct multi-toc tprel relocs

Commit f15d0b54 trimmed some unnecessary TPREL relocs, but missed
changing another place where they are allocated.

	* elf64-ppc.c (ppc_size_one_stub): Fix comment typo.
	(ppc64_elf_layout_multitoc): Allocate relocs for tprel as we
	do in size_dynamic_sections.