scsi: NCR5380: Handle BSY signal loss during information transfer phases

Improve robustness by checking for a lost BSY signal during the information
transfer loop. The status register is being polled anyway, so a BSY check
costs nothing. BSY signal loss could be caused by a target error or a
kicked plug etc. A bus reset is another possibility but that is already
handled and hostdata->connected would be NULL.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Link: https://lore.kernel.org/r/d253dddaf4d9bc17b8ee02ea2b731d92f25b16f1.1723001788.git.fthain@linux-m68k.org


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>