net: mana: Fix possible double free in error handling path

When auxiliary_device_add() returns error and then calls
auxiliary_device_uninit(), callback function adev_release
calls kfree(madev). We shouldn't call kfree(madev) again
in the error handling path. Set 'madev' to NULL.

Fixes: a69839d4 ("net: mana: Add support for auxiliary device")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
Link: https://patch.msgid.link/20240625130314.2661257-1-make24@iscas.ac.cnSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/microsoft/mana/mana_en.c

@@ -2798,6 +2798,8 @@ static int add_adev(struct gdma_dev *gd)
 	if (ret)
 		goto init_fail;
 
+	/* madev is owned by the auxiliary device */
+	madev = NULL;
 	ret = auxiliary_device_add(adev);
 	if (ret)
 		goto add_fail;