haven: doorbell: Add neuron and qrtr labels

Add labels for the neuron and qrtr labels. The neuron block protocol
requires two doorbell pairs and qrtr requires one doorbell pair.

Change-Id: I7d9c3da5ae620209b0d7a374bd487d567efbb97a
Signed-off-by: Chris Lew <clew@codeaurora.org>