x86: fix early_ioremap pagetable ops

Put appropriate pagetable update hooks in so that paravirt knows
what's going on in there.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>