x86: page.h: move pa and va related things

# HG changeset patch
# User Jeremy Fitzhardinge <jeremy@xensource.com>
# Date 1199319656 28800
# Node ID d617b72a0cc9d14bde2087d065c36d4ed3265761
# Parent  3bd7db6e85e66e7f3362874802df26a82fcb2d92
x86: page.h: move pa and va related things

Move and unify the virtual<->physical address space conversion
functions.

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>