pam: keep pin on the PAM stack for forward_pass
Currently only the password or the long-term part of a two-factor
authentication was kept on the PM stack if pam_sss.so has the option
forward_pass. With this patch the Smartcard PIN can be forwarded to
other PAM modules as well.
Related https://pagure.io/SSSD/sssd/issue/4067
Reviewed-by: Pavel Březina <pbrezina@redhat.com>