KVM: Make paravirt tlb flush also reload the PAE PDPTRs

(cherry picked from commit a8cd0244e9cebcf9b358d24c7e7410062f3665cb)

The paravirt tlb flush may be used not only to flush TLBs, but also
to reload the four page-directory-pointer-table entries, as it is used
as a replacement for reloading CR3.  Change the code to do the entire
CR3 reloading dance instead of simply flushing the TLB.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>