1. Sanity check for the SCSI temp_buffer if it's allocated or not.
2. Data reads and writes in non-DMA mode should be accessible only when DMA mode is Idle (as in, no DMA at all, whereas DMA mode will go to the SCSI controllers' callbacks).
CD-ROM side: fixed a mode sense page (0x08 Sony, used by both Sony and Texel drives) as well as corrected the Toshiba specific drive speeds (bytes_per_second).
NCR 5380 side: split the work into the generic 5380 core and the ASICs into separate sources (53c400 and T128) and added the T228 MCA adapter based on the 128.
