Add/test detection of RTX 4000 series cards

[solardiz]

We should probably add a check to get_compute_capability() and maybe to get_processors_count() in opencl_common.c.

[solardiz]

Upon a closer look, that code inget_compute_capability() may be dead anyway? We check for if (!major) { before reaching the "Apple, VCL and some other environments" fallback code that checks device names. However, major is a pointer that is supposed to be non-NULL, or if it happens to actually be NULL then we'd crash on trying to assign values to *major. If this was broken for years, should we drop it? Also, it would be cleaner for that function itself to initialize *major and *minor to 0 rather than rely on each caller having done so (and simplify the callers).

We should still verify the logic of get_processors_count() for 4000 series cards - maybe it's correct as-is (the major >= 7 path does what's needed), or maybe we need to add a major check.

[solardiz]

Upon a closer look, that code inget_compute_capability() may be dead anyway? We check for if (!major) { before reaching the "Apple, VCL and some other environments" fallback code that checks device names. However, major is a pointer that is supposed to be non-NULL

Looks like a bug introduced in 2021 with 8fa21b5, where @magnumripper added detection of a few more card series (IIRC on my suggestion), but apparently broke this all (and I did not catch that in my review). So now we need to decide between fixing that bug vs. dropping this legacy code.