net: pse-pd: pd692x0: reduce stack usage in pd692x0_setup_pi_matrix

The pd692x0_manager array in this function is really too big to fit on the
stack, though this never triggered a warning until a recent patch made
it slightly bigger:

drivers/net/pse-pd/pd692x0.c: In function 'pd692x0_setup_pi_matrix':
drivers/net/pse-pd/pd692x0.c:1210:1: error: the frame size of 1584 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

Change the function to dynamically allocate the array here.

Fixes: 3597540 ("net: pse-pd: pd692x0: Add support for PSE PI priority feature")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20250709153210.1920125-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: arndb

drivers/net/pse-pd/pd692x0.c

@@ -860,7 +860,7 @@ pd692x0_of_get_ports_manager(struct pd692x0_priv *priv,
 
 static int
 pd692x0_of_get_managers(struct pd692x0_priv *priv,
-			struct pd692x0_manager manager[PD692X0_MAX_MANAGERS])
+			struct pd692x0_manager *manager)
 {
 	struct device_node *managers_node, *node;
 	int ret, nmanagers, i, j;
@@ -1164,7 +1164,7 @@ pd692x0_write_ports_matrix(struct pd692x0_priv *priv,
 
 static int pd692x0_setup_pi_matrix(struct pse_controller_dev *pcdev)
 {
-	struct pd692x0_manager manager[PD692X0_MAX_MANAGERS] = {0};
+	struct pd692x0_manager *manager __free(kfree) = NULL;
 	struct pd692x0_priv *priv = to_pd692x0_priv(pcdev);
 	struct pd692x0_matrix port_matrix[PD692X0_MAX_PIS];
 	int ret, i, j, nmanagers;
@@ -1174,6 +1174,10 @@ static int pd692x0_setup_pi_matrix(struct pse_controller_dev *pcdev)
 	    priv->fw_state != PD692X0_FW_COMPLETE)
 		return 0;
 
+	manager = kcalloc(PD692X0_MAX_MANAGERS, sizeof(*manager), GFP_KERNEL);
+	if (!manager)
+		return -ENOMEM;
+
 	ret = pd692x0_of_get_managers(priv, manager);
 	if (ret < 0)
 		return ret;