* scd/app-p15.c (CARD_PRODUCT_NEXUS): New.
(read_p15_info): Detect Nexus cards.
(get_dispserialno): Use product_id instead of comparing the
manufacturer_id.
(do_sign): Handle Nexus like BELPIC.
(cherry picked from commit b83d86b988bbb05b25dba250a5f01b33b3dbb824)