do not use timedwait on qemu_halt_cond

The following conditions can cause cpu_has_work(env) to become true:

- env->queued_work_first: run_on_cpu is already kicking the VCPU

- env->stop = 1: pause_all_vcpus is already kicking the VCPU

- env->stopped = 0: resume_all_vcpus is already kicking the VCPU

- vm_running = 1: vm_start is calling resume_all_vcpus

- env->halted = 0: see previous patch

- qemu_cpu_has_work(env): when it becomes true, board code should set
  env->halted = 0 too.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

cpus.c

@@ -771,7 +771,7 @@ static void qemu_tcg_wait_io_event(void)
     CPUState *env;
 
     while (all_cpu_threads_idle()) {
-        qemu_cond_timedwait(tcg_halt_cond, &qemu_global_mutex, 1000);
+        qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex);
     }
 
     qemu_mutex_unlock(&qemu_global_mutex);
@@ -794,7 +794,7 @@ static void qemu_tcg_wait_io_event(void)
 static void qemu_kvm_wait_io_event(CPUState *env)
 {
     while (cpu_thread_is_idle(env)) {
-        qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);
+        qemu_cond_wait(env->halt_cond, &qemu_global_mutex);
     }
 
     qemu_kvm_eat_signals(env);