cephfs: fix staticcheck comment
cephfs: fix staticcheck comment

getting is unused for linter "staticcheck"
(nolintlint) error message due to wrong
comment format. this the format now with
`//directive // comment`

Signed-off-by: Madhu Rajanna <60fbf37a92c2a0908e31296d18dadbec5a4dae17@gmail.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi