* linux-nat.c (linux_nat_do_thread_registers): Use section size

	* linux-nat.c (linux_nat_do_thread_registers): Use section size
	from gdbarch_core_regset_sections also for .reg if present.

	* amd64-linux-tdep.c (amd64_linux_regset_sections): Fix incorrect
	section size for .reg.
	* ppc-linux-tdep.c (ppc_linux_vsx_regset_sections): Likewise.
	(ppc_linux_vmx_regset_sections): Likewise.
	(ppc_linux_fp_regset_sections): Likewise.
	(ppc64_linux_vsx_regset_sections): New variable.
	(ppc64_linux_vmx_regset_sections): Likewise.
	(ppc64_linux_fp_regset_sections): Likewise.
	(ppc_linux_init_abi): Install core_regset_section lists appropriate
	for current word size.