KVM: LAPIC: make sure IRR bitmap is scanned after vm load

The vcpus are initialized with irr_pending set to false, but
loading the LAPIC registers with pending IRR fails to reset
the irr_pending variable.

Cc: stable@kernel.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>