Runtime unavailability of unified shared memory not disclosed by libomptarget

[KaruroChori]

I found the issue at least in my case. Debian official kernel images are built without CONFIG_DEVICE_PRIVATE.
Which is needed for this feature to work.
https://forums.developer.nvidia.com/t/how-to-enable-hmm-on-debian/316561

Time to rebuild the kernel.

Addendum: I can confirm that with the freshly baked kernel it works.

Originally posted by @KaruroChori in #127334

Debian's kernel images, and possibly others, don't ship with support for USM out of the box.
At runtime, applications which have been built with #pragma omp requires unified_shared_memory are going to fail without providing any meaningful error message which describes the issue.
It would be nice if libomptarget could perform a check at runtime and provide a more meaningful error message for this type of failure.