platform/x86: dell-laptop: fix missing cleanups in init error path

In the Linux kernel, the following vulnerability has been resolved: platform/x86: dell-laptop: fix missing cleanups in init error path dell_init() initializes several resources after dell_setup_rfkill(), including the optional touchpad LED, keyboard backlight LED, battery hook, debugfs directory and dell-laptop notifier. If a later LED or backlight registration fails, the error path only tears down the battery hook and rfkill resources. This leaves the notifier, debugfs directory, keyboard backlight LED and optional touchpad LED registered after dell_init() returns an error. Add the missing cleanup calls before tearing down rfkill.