sysfs: add sysfs_group{s}_change_owner()

sysfs: add sysfs_group{s}_change_owner()

BugLink: https://bugs.launchpad.net/bugs/1865359
Add helpers to change the owner of sysfs groups.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 303a42769c4c4d8e5e3ad928df87eb36f8c1fa60 linux-next)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>