afs: Return ENOENT if no cell DNS record can be found

afs: Return ENOENT if no cell DNS record can be found

[ Upstream commit 0167236e7d66c5e1e85d902a6abc2529b7544539 ]

Make AFS return error ENOENT if no cell SRV or AFSDB DNS record (or
cellservdb config file record) can be found rather than returning
EDESTADDRREQ.

Also add cell name lookup info to the cursor dump.

Fixes: d5c32c89b208 ("afs: Fix cell DNS lookup")
Reported-by: Markus Suvanto <markus.suvanto@gmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216637
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>