For KVM we need to store some information in the PACA, so we
need to extend it.

This patch adds KVM SLB shadow related entries to the PACA and
a field that indicates if we're inside a guest.
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>