ld/x86-64: Also set LAM_U57 when setting LAM_U48

Since LAM_U48 implies LAM_U57, also set LAM_U57 when setting LAM_U48.

bfd/

	* elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): Also set
	LAM_U57 when setting LAM_U48.

ld/

	* ld-x86-64/property-x86-lam-u48-4.d: Updated.
	* ld-x86-64/property-x86-lam-u48-5.d: Likewise.