Enable ppc476 workaround for ld -r.

Enable ppc476 workaround for ld -r.

The Linux kernel builds modules using ld -r.  These might need the
ppc476 workaround, so enable it for ld -r if sections have sufficient
alignment to tell location within a page.

bfd/
	* elf32-ppc.c (ppc_elf_relax_section): Enable ppc476 workaround
	for ld -r, when code sections are sufficiently aligned.
	* elf32-ppc.h (struct ppc_elf_params): Delete pagesize.  Add
	pagesize_p2.
ld/
	* emultempl/ppc32elf.em (pagesize): New static var.
	(ppc_after_open_output): Set params.pagesize_p2 from pagesize.
	(PARSE_AND_LIST_ARGS_CASES): Adjust to use pagesize.