Disable EE when calling nap.
Disable EE when calling nap.

    Due to the LPCR values, nap can already be exited by an
    interrupt or decrementer event.  Remove EE in the MSR so
    that we are guarenteed that we fully enter nap even if
    there is a interrupt or decrementer pending.

Change-Id: If70f82ea7c05576c1dd97de9e2a1d930c36ba46f
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/1515
Tested-by: Jenkins Server
Reviewed-by: Daniel M. Crowell <912029ca9254ac7b5854e56910561d682e1fa2d0@us.ibm.com>
Reviewed-by: Douglas R. Gilbert <54dff2264884c355ed5584a3b7f1530b4b26921e@us.ibm.com>
Reviewed-by: A. Patrick Williams III <c87e37b1a4035affd737b461af89fb722d635f4d@us.ibm.com>

csmart/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot,open-power/hostboot,csmart/hostboot,csmart/hostboot,open-power/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,alvintpwang/hostboot,alvintpwang/hostboot,alvintpwang/hostboot,open-power/hostboot,csmart/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,alvintpwang/hostboot