i2c: scmi: Fix probe error on devices with an empty SMB0001 ACPI device node

Some AMD based HP laptops have a SMB0001 ACPI device node which does not
define any methods.

This leads to the following error in dmesg:

[    5.222731] cmi: probe of SMB0001:00 failed with error -5

This commit makes acpi_smbus_cmi_add() return -ENODEV instead in this case
silencing the error. In case of a failure of the i2c_add_adapter() call
this commit now propagates the error from that call instead of -EIO.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-scmi.c

@@ -367,6 +367,7 @@ static int acpi_smbus_cmi_add(struct acpi_device *device)
 {
 	struct acpi_smbus_cmi *smbus_cmi;
 	const struct acpi_device_id *id;
+	int ret;
 
 	smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 	if (!smbus_cmi)
@@ -388,8 +389,10 @@ static int acpi_smbus_cmi_add(struct acpi_device *device)
 	acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 			    acpi_smbus_cmi_query_methods, NULL, smbus_cmi, NULL);
 
-	if (smbus_cmi->cap_info == 0)
+	if (smbus_cmi->cap_info == 0) {
+		ret = -ENODEV;
 		goto err;
+	}
 
 	snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 		"SMBus CMI adapter %s",
@@ -400,7 +403,8 @@ static int acpi_smbus_cmi_add(struct acpi_device *device)
 	smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 	smbus_cmi->adapter.dev.parent = &device->dev;
 
-	if (i2c_add_adapter(&smbus_cmi->adapter)) {
+	ret = i2c_add_adapter(&smbus_cmi->adapter);
+	if (ret) {
 		dev_err(&device->dev, "Couldn't register adapter!\n");
 		goto err;
 	}
@@ -410,7 +414,7 @@ static int acpi_smbus_cmi_add(struct acpi_device *device)
 err:
 	kfree(smbus_cmi);
 	device->driver_data = NULL;
-	return -EIO;
+	return ret;
 }
 
 static int acpi_smbus_cmi_remove(struct acpi_device *device)