* scd/iso7816.h (struct pininfo_s): Remove MODE and add FIXEDLEN.
* scd/app-dinsig.c (verify_pin): Initialize FIXEDLEN to unknown.
* scd/app-nks.c (verify_pin): Likewise.
* scd/app-openpgp.c (verify_a_chv, verify_chv3, do_change_pin):
Likewise.
* scd/apdu.c (check_pcsc_keypad): Add comment.
(pcsc_keypad_verify, pcsc_keypad_modify): PC/SC driver only support
readers with the feature of variable length input (yet).
(apdu_check_keypad): Set FIXEDLEN.
* scd/ccid-driver.c (ccid_transceive_secure): Add GEMPC_PINPAD
specific settings.
Support fixed length PIN input for keypad.