Revert "dpif-netdev: Use compatible function type to fix broken build."

Commit ab15e70eb5 ("dpctl: Expand the flow dump type filter") will be
reverted, which this patch fixed, so it needs to be reverted as well.

This reverts commit b10ac77221.

CC: Gavi Teitz <gavi@mellanox.com>
CC: Simon Horman <simon.horman@netronome.com>
CC: Roi Dayan <roid@mellanox.com>
CC: Aaron Conole <aconole@redhat.com>
Signed-off-by: Justin Pettit <jpettit@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>

lib/dpif-netdev.c

@@ -3481,7 +3481,7 @@ dpif_netdev_flow_dump_cast(struct dpif_flow_dump *dump)
 
 static struct dpif_flow_dump *
 dpif_netdev_flow_dump_create(const struct dpif *dpif_, bool terse,
-                             struct dpif_flow_dump_types *type OVS_UNUSED)
+                             char *type OVS_UNUSED)
 {
     struct dpif_netdev_flow_dump *dump;