client: transmit RSPRO via bankd_conn_fsm

This fixes a crash where the modem/phone would sent APDUs at a time
when there is no connection to the bankd yet.  If we transmit the
RSPRO PDUs via the FSM, this cannot happen.

Change-Id: I965666ae4622c403e63c060deaa4d80e9249d155
diff --git a/src/client.h b/src/client.h
index 5df5e67..80edaa3 100644
--- a/src/client.h
+++ b/src/client.h
@@ -16,6 +16,7 @@
 	BDC_E_TCP_UP,		/* notify BDC that TCP connection is up/connected */
 	BDC_E_TCP_DOWN,		/* notify BDC that TCP connection is down/disconnected */
 	BDC_E_CLIENT_CONN_RES,	/* notify BDC that ClientConnectRes has been received */
+	BDC_E_RSPRO_TX,		/* transmit a RSPRO PDU to the bankd */
 };
 
 extern struct osmo_fsm remsim_client_bankd_fsm;