[GOLD] Re: PowerPC64: Don't pretend to support multi-toc

We can't get at section->address() until everything is laid out, so
trying to generalise the offset calculation rather than using a value
of 0x8000 (the old object->toc_base_offset()) was bound to fail.
got->g_o_t() is a little better than a hard-coded 0x8000.

	* powerpc.cc (Target_powerpc::Scan::local, global): Don't use
	toc_pointer() here.