firmware/sniffer: Fix programming error in PPS

process_byte_pps() would never enter the error path in which the
first byte would be != 0xff.  However, the caller already verified
this before calling process_byte_pps() so the error path should
never be hit anyway.

Change-Id: Ia74b6338219a6965e6bd35a6efcf369890e02d81

firmware/libcommon/source/sniffer.c

@@ -595,7 +595,7 @@ static void process_byte_pps(uint8_t byte)
 	switch (pps_state) { /* see ISO/IEC 7816-3:2006 section 9.2 */
 	case PPS_S_WAIT_PPSS: /*!< initial byte */
 		flags = 0;
-		if (0xff) {
+		if (byte == 0xff) {
 			pps_cur[0] = byte;
 			pps_state = PPS_S_WAIT_PPS0; /* go to next state */
 		} else {