[xsigo] Avoid storing unused uninitialised fields in gateway address

As reported by Coverity, xsmp_rx_xve_modify() currently passes a
partially initialised struct ib_address_vector to xve_update_tca() and
thence to eoib_set_gateway(), which uses memcpy() to store the whole
structure including the (unused and unneeded) uninitialised fields.

Silence the Coverity warning by zeroing the whole structure.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/infiniband/xsigo.c

@@ -870,6 +870,7 @@ static int xsmp_rx_xve_modify ( struct xsigo_manager *xcm,
 	 * erroneously transmitted as little-endian.
 	 */
 	mtu = ntohs ( msg->mtu );
+	memset ( &tca, 0, sizeof ( tca ) );
 	tca.qpn = ntohl ( msg->tca.data );
 	tca.qkey = ntohs ( msg->tca.qkey );
 	tca.gid_present = 1;