ccid_slot_fsm: Don't free ATR msgb; it is persistent

Change-Id: I2b153c7ad1f40dff946b51d743b2740c4db10dae
diff --git a/ccid_common/ccid_slot_fsm.c b/ccid_common/ccid_slot_fsm.c
index 59071de..90899bd 100644
--- a/ccid_common/ccid_slot_fsm.c
+++ b/ccid_common/ccid_slot_fsm.c
@@ -95,7 +95,7 @@
 		resp = ccid_gen_data_block(cs, ss->seq, CCID_CMD_STATUS_OK, 0,
 					   msgb_data(tpdu), msgb_length(tpdu));
 		ccid_slot_send_unbusy(cs, resp);
-		msgb_free(tpdu);
+		/* Don't free "TPDU" here, as the ATR should survive */
 		break;
 	case ISO7816_E_TPDU_DONE_IND:
 		tpdu = data;