ocxl: Remove the unused declarations in headr file

The definition of ocxl_create_cdev() and ocxl_destroy_cdev() has been
removed since commit 75ca758a ("ocxl: Create a clear delineation
between ocxl backend & frontend"). So, let's remove the empty declarations.

Signed-off-by: Zhang Zekun <zhangzekun11@huawei.com>
Link: https://lore.kernel.org/r/20240907082555.60836-1-zhangzekun11@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>