net: openvswitch: Remove invalid comment

During pre-upstream development, the openvswitch datapath used a custom
hashtable to store vports that could fail on delete due to lack of
memory. However, prior to upstream submission, this code was reworked to
use an hlist based hastable with flexible-array based buckets. As such
the failure condition was eliminated from the vport_del path, rendering
this comment invalid.

Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: David S. Miller <davem@davemloft.net>