pcf50633-charger: Add missing sysfs_remove_group()

sysfs entries should be removed when unload the module.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
diff --git a/drivers/power/pcf50633-charger.c b/drivers/power/pcf50633-charger.c
index 066f994..4fa52e1 100644
--- a/drivers/power/pcf50633-charger.c
+++ b/drivers/power/pcf50633-charger.c
@@ -456,6 +456,7 @@
 	for (i = 0; i < ARRAY_SIZE(mbc_irq_handlers); i++)
 		pcf50633_free_irq(mbc->pcf, mbc_irq_handlers[i]);
 
+	sysfs_remove_group(&pdev->dev.kobj, &mbc_attr_group);
 	power_supply_unregister(&mbc->usb);
 	power_supply_unregister(&mbc->adapter);
 	power_supply_unregister(&mbc->ac);