SCD: Add option enable-keypad-varlen and support for GEMPC_PINPAD.
* scd/scdaemon.h (opt): Add enable_keypad_varlen. * scd/scdaemon.c (cmd_and_opt_values): Add oEnableKeypadVarlen. (opts, main): Add oEnableKeypadVarlen. * scd/ccid-driver.c (GEMPC_PINPAD): New. (ccid_transceive_secure): Add enable_varlen handling. Enable GEMPC_PINPAD.
Note that GEMPC_PINPAD doesn't support variable length keypad input.
The feature of fixed length keypad input will be added soon.