fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal

In the Linux kernel, the following vulnerability has been resolved:

fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal

CXL is linked before fwctl in drivers/Makefile. Both use `module_init, so

`cxl_pci_driver_init()` runs first. When `cxl_pci_probe()` calls

`fwctl_register()` and then `device_add()`, fwctl_class is not yet

registered because fwctl_init() hasn't run, causing `class_to_subsys()` to

return NULL and skip knode_class initialization.

On device removal, `class_to_subsys()` returns non-NULL, and

`device_del()` calls `klist_del()` on the uninitialized knode, triggering

a NULL pointer dereference.