[OpenMP] LIBOMPTARGET_DEVICE_ARCHITECTURES requires semicolons (#107454)

If I use commas to delimit architectures in
`LIBOMPTARGET_DEVICE_ARCHITECTURES`, cmake for the runtimes complains:

```
Unknown GPU architecture 'sm_70,sm_80,sm_90'
```

Semicolons are required instead.

GitOrigin-RevId: 54b10555c32e9677ce15c408296f92b35cd3d29c
1 file changed