dsa: do not dereference non-existing routing table
dsa: do not dereference non-existing routing table

In the case where there is only one switch, no routing table will have
been allocated, so do not dereference it in this case.

Signed-off-by: Tobias Waldekranz <059b8b880f8441509ec8a65b50b4c6ae74ebea76@waldekranz.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs