serial: zero struct mctp_binding_serial on init

Ensure we're starting from a known state.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Change-Id: I342b43f3b7bf219af3224966d62a5a6869e99f02
diff --git a/serial.c b/serial.c
index 4ad259f..7e27b1c 100644
--- a/serial.c
+++ b/serial.c
@@ -299,6 +299,7 @@
 	struct mctp_binding_serial *serial;
 
 	serial = __mctp_alloc(sizeof(*serial));
+	memset(serial, 0, sizeof(*serial));
 	serial->fd = -1;
 	serial->rx_state = STATE_WAIT_SYNC_START;
 	serial->rx_pkt = NULL;