Revert "smb: client: fix chmod(2) regression with ATTR_READONLY"

JIRA: INTERNAL
Upstream Status: RHEL Only

This reverts commit 3777501a because
it went it by accident during Exception/Blocker period (dist-git policy
already allowed 10.0.z content so it passed policy check).

Signed-off-by: Jan Stancek <jstancek@redhat.com>