drivers/input/ft5x06.c: Remove cool logic to disable polling when there there...

drivers/input/ft5x06.c:  Remove cool logic to disable polling when there there is no client waiting for read data.  That was a great idea to save CPU cycles when there is nothing reading from the touchscrren but, unfortunately, does not work with readers that open the driver in non-blocking mode.  So I think we just have to eat the CPUs even when there is nothing waiting for touchscreen input.