[SSSD] [sssd PR#5401][comment] authtok: add label to Smartcard token

[alexey-tikhonov]

URL: https://github.com/SSSD/sssd/pull/5401
Title: #5401: authtok: add label to Smartcard token

alexey-tikhonov commented:
"""
Now in `pamsrv_p11.c::pack_cert_data()` we pass `label` to `pam_sss` twice: once as part of a `prompt` and once as a `label`, right?

I have few very minor remarks, please see inline.
"""

See the full comment at https://github.com/SSSD/sssd/pull/5401#issuecomment-743449279