[PATCH] x86_64 machine_kexec: Use standard pagetable helpers

Use the standard hardware page table manipulation macros.
This is possible now that linux works with all 4 levels
of the page tables.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>