TTY: amiserial, remove unnecessary platform_set_drvdata()

The driver core clears the driver data to NULL after device_release
or on probe failure. Thus, it is not needed to manually clear the
device driver data to NULL.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/amiserial.c

@@ -1785,8 +1785,6 @@ static int __exit amiga_serial_remove(struct platform_device *pdev)
 	free_irq(IRQ_AMIGA_TBE, state);
 	free_irq(IRQ_AMIGA_RBF, state);
 
-	platform_set_drvdata(pdev, NULL);
-
 	return error;
 }