hw/hyperv/syndbg: skip automatic zero-init of large array

hw/hyperv/syndbg: skip automatic zero-init of large array

The 'handle_recv_msg' method has a 4k byte array used for copying
data between the network socket and guest memory. Skip the automatic
zero-init of this array to eliminate the performance overhead in the
I/O hot path.

The 'data_buf' array will be fully initialized when data is read
off the network socket.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-18-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>