scd: Internal CCID driver thing only for SPR532.

* scd/ccid-driver.c (ccid_vendor_specific_setup): New.  Limit
only for SPR532, excluding other readers by SCM.
(ccid_slot_status): Use ccid_vendor_specific_setup.

We follow the setup procedure of libccid implementation, which sends
the escape command for SPR532 only.

• Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>