sysfs: add sysfs_create/remove_groups()

These functions are being open-coded in 3 different places in the driver
core, and other driver subsystems will want to start doing this as well,
so move it to the sysfs core to keep it all in one place, where we know
it is written properly.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 89db726..c7efccb 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -126,31 +126,13 @@
 int driver_add_groups(struct device_driver *drv,
 		      const struct attribute_group **groups)
 {
-	int error = 0;
-	int i;
-
-	if (groups) {
-		for (i = 0; groups[i]; i++) {
-			error = sysfs_create_group(&drv->p->kobj, groups[i]);
-			if (error) {
-				while (--i >= 0)
-					sysfs_remove_group(&drv->p->kobj,
-							   groups[i]);
-				break;
-			}
-		}
-	}
-	return error;
+	return sysfs_create_groups(&drv->p->kobj, groups);
 }
 
 void driver_remove_groups(struct device_driver *drv,
 			  const struct attribute_group **groups)
 {
-	int i;
-
-	if (groups)
-		for (i = 0; groups[i]; i++)
-			sysfs_remove_group(&drv->p->kobj, groups[i]);
+	sysfs_remove_groups(&drv->p->kobj, groups);
 }
 
 /**