switchdev: fdb filter_dev is always NULL for self (device), so remove check

Remove the filter_dev check when dumping fdb entries, otherwise dump
returns empty list.  filter_dev is always passed as NULL when dumping fdbs
on SELF.  We want the fdbs installed on the device to be listed in the
dump.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Fixes: 45d4122c ("switchdev: add support for fdb add/del/dump via switchdev_port_obj ops")
Acked-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>