net: dsa: Do not make user port errors fatal

commit 86f8b1c0 upstream.

Prior to 1d27732f ("net: dsa: setup and teardown ports"), we would
not treat failures to set-up an user port as fatal, but after this
commit we would, which is a regression for some systems where interfaces
may be declared in the Device Tree, but the underlying hardware may not
be present (pluggable daughter cards for instance).

Fixes: 1d27732f ("net: dsa: setup and teardown ports")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/dsa/dsa2.c

@@ -412,7 +412,7 @@ static int dsa_tree_setup_switches(struct dsa_switch_tree *dst)
 
 		err = dsa_switch_setup(ds);
 		if (err)
-			return err;
+			continue;
 
 		for (port = 0; port < ds->num_ports; port++) {
 			dp = &ds->ports[port];