x86: page.h: unify page copying and clearing

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199317362 28800
# Node ID 4d9a413a0f4c1d98dbea704f0366457b5117045d
# Parent  ba0ec40a50a7aef1a3153cea124c35e261f5a2df
x86: page.h: unify page copying and clearing

Move, and to some extent unify, the various page copying and clearing
functions.  The only unification here is that both architectures use
the same function for copying/clearing user and kernel pages.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>