cpus: remove icount handling from qemu_tcg_cpu_thread_fn

We should never be running in multi-threaded mode with icount enabled.
There is no point calling handle_icount_deadline here so remove it and
assert !use_icount.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

cpus.c

@@ -1392,6 +1392,8 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
 {
     CPUState *cpu = arg;
 
+    g_assert(!use_icount);
+
     rcu_register_thread();
 
     qemu_mutex_lock_iothread();
@@ -1434,8 +1436,6 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
             }
         }
 
-        handle_icount_deadline();
-
         atomic_mb_set(&cpu->exit_request, 0);
         qemu_tcg_wait_io_event(cpu);
     }