fbdev: uvesafb: unregister connector callback on init failure

In the Linux kernel, the following vulnerability has been resolved: fbdev: uvesafb: unregister connector callback on init failure uvesafb_init() registers the v86d connector callback before registering the platform driver. If platform_driver_register() fails, the function returns the error directly and leaves the connector callback registered. The later platform-device failure path already unregisters the callback. Add the same cleanup before the final return when platform-driver registration fails. This issue was identified during our ongoing static-analysis research while reviewing kernel code.

Where it's fixed