VME: restore bus_remove function causing incomplete module unload

Commit 050c3d52cc7810d9d17b8cd231708609af6876ae ("vme: make core
vme support explicitly non-modular") dropped the remove function
because it appeared as if it was for removal of the bus, which is
not supported.

However, vme_bus_remove() is called when a VME device is removed
from the bus and not when the bus is removed; as it calls the VME
device driver's cleanup function.  Without this function, the
remove() in the VME device driver is never called and VME device
drivers cannot be reloaded again.

Here we restore the remove function that was deleted in that
commit, and the reference to the function in the bus structure.

Fixes: 050c3d52cc78 ("vme: make core vme support explicitly non-modular")
Cc: Manohar Vanga <manohar.vanga@gmail.com>
Acked-by: Martyn Welch <martyn@welchs.me.uk>
Cc: devel@driverdev.osuosl.org
Signed-off-by: Stefano Babic <sbabic@denx.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: stable <stable@vger.kernel.org> # 4.9
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/vme/vme.c

@@ -1625,10 +1625,25 @@ static int vme_bus_probe(struct device *dev)
 	return retval;
 }
 
+static int vme_bus_remove(struct device *dev)
+{
+	int retval = -ENODEV;
+	struct vme_driver *driver;
+	struct vme_dev *vdev = dev_to_vme_dev(dev);
+
+	driver = dev->platform_data;
+
+	if (driver->remove != NULL)
+		retval = driver->remove(vdev);
+
+	return retval;
+}
+
 struct bus_type vme_bus_type = {
 	.name = "vme",
 	.match = vme_bus_match,
 	.probe = vme_bus_probe,
+	.remove = vme_bus_remove,
 };
 EXPORT_SYMBOL(vme_bus_type);