net: qrtr: Add forwarding support based on net id

Add support for QRTR to forward messages between network clusters. The
network subnet id's are attached to the QRTR subnodes in the MHI and
RPMSG/GLINK nodes.

The current forwarding decisions are done based on the net ids and are
wrapped in a single function for easier maintenance of forwarding
decisions later on. The function will return true once it determines
a subnet has no connection to another subnet.

The NEW_SERVER, DEL_SERVER, and DEL_CLIENT control messages should be
forwarded while the DATA and RESUME_TX commands should be passed along
to their destination node.

The nameservice is expected to send NEW_SERVER commands for it's entire
database instead of just the local service database with these changes.
This is to make sure new nodes get service notifications that came
earlier and were meant to be forwarded to the new node.

This change squashes the following commits from msm-4.14:
  commit e5f6a6769ceb ("net: qrtr: Add forwarding support based on net id")
  commit 4516ab18718d ("net: qrtr: avoid deadlock in case of recursive
                        lock for node list")
  commit dc2d47cd12d3 ("net: qrtr: Only update pkts with broadcast node
                        ID")
  commit 4277aebeff91 ("net: qrtr: Free skb if qrtr_node_lookup fails
                        during qrtr_fwd_pkt")

In addition fix minor format issues and update copyright.

Change-Id: Iaf01dd212b07dfbb13ec087ea0aae980cda7c2fd
Signed-off-by: Chris Lew <clew@codeaurora.org>