x86/lapic: Load LAPIC state at post_load

x86/lapic: Load LAPIC state at post_load

Load the LAPIC state during post_load (rather than when the CPU
starts).

This allows an interrupt to be delivered from the ioapic to
the lapic prior to cpu loading, in particular the RTC that starts
ticking as soon as we load it's state.

Fixes a case where Windows hangs after migration due to RTC interrupts
disappearing.

Signed-off-by: Dr. David Alan Gilbert <[email protected]>
Suggested-by: Paolo Bonzini <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>