bus: moxtet: remove set but not used variable 'dummy'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/bus/moxtet.c: In function moxtet_remove:
drivers/bus/moxtet.c:822:6: warning: variable dummy set but not used
[-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20190822010351.15660-3-marek.behun@nic.czSigned-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/bus/moxtet.c

@@ -819,7 +819,6 @@ static int moxtet_probe(struct spi_device *spi)
 static int moxtet_remove(struct spi_device *spi)
 {
 	struct moxtet *moxtet = spi_get_drvdata(spi);
-	int dummy;
 
 	free_irq(moxtet->dev_irq, moxtet);
 
@@ -827,7 +826,7 @@ static int moxtet_remove(struct spi_device *spi)
 
 	moxtet_unregister_debugfs(moxtet);
 
-	dummy = device_for_each_child(moxtet->dev, NULL, __unregister);
+	device_for_each_child(moxtet->dev, NULL, __unregister);
 
 	mutex_destroy(&moxtet->lock);