pse-core: Conditionally set current limit during PI regulator registration

Fix an issue where `devm_regulator_register()` would fail for PSE
controllers that do not support current limit control, such as simple
GPIO-based controllers like the podl-pse-regulator. The
`REGULATOR_CHANGE_CURRENT` flag and `max_uA` constraint are now
conditionally set only if the `pi_set_current_limit` operation is
supported. This change prevents the regulator registration routine from
attempting to call `pse_pi_set_current_limit()`, which would return
`-EOPNOTSUPP` and cause the registration to fail.

Fixes: 4a83abc ("net: pse-pd: Add new power limit get and set c33 features")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Tested-by: Kyle Swenson <kyle.swenson@est.tech>
Link: https://patch.msgid.link/20240813073719.2304633-1-o.rempel@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: olerem

drivers/net/pse-pd/pse_core.c

@@ -401,9 +401,14 @@ devm_pse_pi_regulator_register(struct pse_controller_dev *pcdev,
 	rdesc->ops = &pse_pi_ops;
 	rdesc->owner = pcdev->owner;
 
-	rinit_data->constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS |
-						 REGULATOR_CHANGE_CURRENT;
-	rinit_data->constraints.max_uA = MAX_PI_CURRENT;
+	rinit_data->constraints.valid_ops_mask = REGULATOR_CHANGE_STATUS;
+
+	if (pcdev->ops->pi_set_current_limit) {
+		rinit_data->constraints.valid_ops_mask |=
+			REGULATOR_CHANGE_CURRENT;
+		rinit_data->constraints.max_uA = MAX_PI_CURRENT;
+	}
+
 	rinit_data->supply_regulator = "vpwr";
 
 	rconfig.dev = pcdev->dev;