Impact: work around boot crash

Work around Intel Atom erratum AAH41 (probabilistically) - it's triggering
in the field.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Tested-by: NKyle McMartin <kyle@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>