Redundant result check leading to dead code was probably indicative
of a missing return value check of acr122_usb_send_apdu()
Problem reported by Coverity:
at_least: At condition "res < 0", the value of "res" must be at least 12.
cannot_single: At condition "res < 0", the value of "res" cannot be equal to -6.
dead_error_condition: The condition "res < 0" cannot be true.
CID 1090327 (#1 of 1): Logically dead code (DEADCODE)
dead_error_begin: Execution cannot reach this statement "acr122_usb_ack(pnd);".