KVM: LAPIC: Don't need to wakeup vCPU twice afer timer fire

kvm_set_pending_timer() will take care to wake up the sleeping vCPU which
has pending timer, don't need to check this in apic_timer_expired() again.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>