driver core: fix smatch warning on dev->bus check

Commit d42a09802174 (driver core: skip removal test for non-removable
drivers) introduced a smatch warning:

drivers/base/dd.c:386 really_probe()
         warn: variable dereferenced before check 'dev->bus' (see line 373)

Fix the warning by removing the dev->bus NULL check. dev->bus will never
be NULL, so the check was unnecessary.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/dd.c

@@ -384,7 +384,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	if (test_remove) {
 		test_remove = false;
 
-		if (dev->bus && dev->bus->remove)
+		if (dev->bus->remove)
 			dev->bus->remove(dev);
 		else if (drv->remove)
 			drv->remove(dev);