USB: apple-mfi-fastcharge: Fix use after free in probe

This code frees "mfi" and then derefences it on the next line to get
the error code.

Fixes: b0eec52fbe63 ("USB: apple-mfi-fastcharge: Fix kfree after failed kzalloc")
Reviewed-by: Bastien Nocera <[e-mail]>
Signed-off-by: Dan Carpenter <[e-mail]>
Link: https://lore.kernel.org/r/X8ik4j8yJitVUyfU@mwanda
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/apple-mfi-fastcharge.c

···
 {
 	struct power_supply_config battery_cfg = {};
 	struct mfi_device *mfi = NULL;
+	int err;
 
 	if (!mfi_fc_match(udev))
 		return -ENODEV;
···
 						&battery_cfg);
 	if (IS_ERR(mfi->battery)) {
 		dev_err(&udev->dev, "Can't register battery\n");
+		err = PTR_ERR(mfi->battery);
 		kfree(mfi);
-		return PTR_ERR(mfi->battery);
+		return err;
 	}
 
 	mfi->udev = usb_get_dev(udev);