accel/ivpu: Validate firmware log buffer metadata

In the Linux kernel, the following vulnerability has been resolved: accel/ivpu: Validate firmware log buffer metadata The tracing log headers parsed by fw_log_print_buffer() reside in DMA-shared BOs that the NPU firmware can write to. fw_log_from_bo() validated log->header_size and log->size, but fw_log_print_buffer() re-read those same fields from shared memory afterwards, allowing a TOCTOU where firmware changes them between the check and the use, and making the host dereference out-of-bounds addresses while printing logs. Snapshot the validated values once with READ_ONCE() and pass them down explicitly in a new struct ivpu_fw_log_desc instead of re-reading them from the shared struct.