docs: netdev: document patchwork patch states

The patchwork states are largely self-explanatory but small
ambiguities may still come up. Document how we interpret
the states in networking.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: kuba-moo

Documentation/process/maintainer-netdev.rst

@@ -120,7 +120,37 @@ queue for netdev:
   https://patchwork.kernel.org/project/netdevbpf/list/
 
 The "State" field will tell you exactly where things are at with your
-patch. Patches are indexed by the ``Message-ID`` header of the emails
+patch:
+
+================== =============================================================
+Patch state        Description
+================== =============================================================
+New, Under review  pending review, patch is in the maintainer’s queue for
+                   review; the two states are used interchangeably (depending on
+                   the exact co-maintainer handling patchwork at the time)
+Accepted           patch was applied to the appropriate networking tree, this is
+                   usually set automatically by the pw-bot
+Needs ACK          waiting for an ack from an area expert or testing
+Changes requested  patch has not passed the review, new revision is expected
+                   with appropriate code and commit message changes
+Rejected           patch has been rejected and new revision is not expected
+Not applicable     patch is expected to be applied outside of the networking
+                   subsystem
+Awaiting upstream  patch should be reviewed and handled by appropriate
+                   sub-maintainer, who will send it on to the networking trees;
+                   patches set to ``Awaiting upstream`` in netdev's patchwork
+                   will usually remain in this state, whether the sub-maintainer
+                   requested changes, accepted or rejected the patch
+Deferred           patch needs to be reposted later, usually due to dependency
+                   or because it was posted for a closed tree
+Superseded         new version of the patch was posted, usually set by the
+                   pw-bot
+RFC                not to be applied, usually not in maintainer’s review queue,
+                   pw-bot can automatically set patches to this state based
+                   on subject tags
+================== =============================================================
+
+Patches are indexed by the ``Message-ID`` header of the emails
 which carried them so if you have trouble finding your patch append
 the value of ``Message-ID`` to the URL above.