Input: evdev - add a schedule point in evdev_write()

Large writes to evdev interface may cause rcu stalls. Let's add
cond_resched() to the loop to avoid this.

Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/evdev.c

@@ -564,6 +564,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer,
 
 		input_inject_event(&evdev->handle,
 				   event.type, event.code, event.value);
+		cond_resched();
 	}
 
  out: