NFC: hci: Add pipes table to reference them with a tuple {gate, host}

In order to keep host source information on specific hci event (such as
evt_connectivity or evt_transaction) and because 2 pipes can be connected
to the same gate, it is necessary to add a table referencing every pipe
with a {gate, host} tuple.

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