NFC: st-nci: initialize gate_count in st_nci_hci_network_init

When initializing ndev->hci_dev->init_data, only gates field
was set. gate_count needs to be initialized as well.

Cc: stable@vger.kernel.org
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>