usb: misc: onboard_usb_dev: fix build warning for CONFIG_USB_ONBOARD_DEV_USB5744=n

When the USB5744 option is disabled, the onboard_usb driver warns about
unused functions:

drivers/usb/misc/onboard_usb_dev.c:358:12: error: 'onboard_dev_5744_i2c_write_byte' defined but not used [-Werror=unused-function]
  358 | static int onboard_dev_5744_i2c_write_byte(struct i2c_client *client, u16 addr, u8 data)
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/usb/misc/onboard_usb_dev.c:313:12: error: 'onboard_dev_5744_i2c_read_byte' defined but not used [-Werror=unused-function]
  313 | static int onboard_dev_5744_i2c_read_byte(struct i2c_client *client, u16 addr, u8 *data)
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Extend the #ifdef block a little further to cover all of these functions.
Ideally we'd use use if(IS_ENABLED()) instead, but that doesn't currently
work because the i2c_transfer() and i2c_smbus_write_word_data() function
declarations are hidden  when CONFIG_I2C is disabled.

Fixes: 1143d41 ("usb: misc: onboard_usb_dev: Fix usb5744 initialization sequence")
Signed-off-by: Arnd Bergmann <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: arndb

drivers/usb/misc/onboard_usb_dev.c

@@ -310,6 +310,7 @@ static void onboard_dev_attach_usb_driver(struct work_struct *work)
 		pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
 }
 
+#if IS_ENABLED(CONFIG_USB_ONBOARD_DEV_USB5744)
 static int onboard_dev_5744_i2c_read_byte(struct i2c_client *client, u16 addr, u8 *data)
 {
 	struct i2c_msg msg[2];
@@ -388,7 +389,6 @@ static int onboard_dev_5744_i2c_write_byte(struct i2c_client *client, u16 addr,
 
 static int onboard_dev_5744_i2c_init(struct i2c_client *client)
 {
-#if IS_ENABLED(CONFIG_USB_ONBOARD_DEV_USB5744)
 	struct device *dev = &client->dev;
 	int ret;
 	u8 reg;
@@ -417,10 +417,13 @@ static int onboard_dev_5744_i2c_init(struct i2c_client *client)
 		return dev_err_probe(dev, ret, "USB Attach with SMBus command failed\n");
 
 	return ret;
+}
 #else
+static int onboard_dev_5744_i2c_init(struct i2c_client *client)
+{
 	return -ENODEV;
-#endif
 }
+#endif
 
 static int onboard_dev_probe(struct platform_device *pdev)
 {