input: do not take reference of parent input object

This is currently broken, anyway as we do not unref the object. However, if we
take a reference, then kmscon_input_unref() would never destroy the object as
there are still references. The caller would have to call kmscon_input_sleep()
first to have the desired effect.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

src/input.c

@@ -180,7 +180,6 @@ static int kmscon_input_device_new(struct kmscon_input_device **out,
 		return -ENOMEM;
 	}
 
-	kmscon_input_ref(input);
 	device->input = input;
 	device->rfd = -1;