scsi: NCR5380: Initialize buffer for MSG IN and STATUS transfers

Following an incomplete transfer in MSG IN phase, the driver would not
notice the problem and would make use of invalid data. Initialize 'tmp'
appropriately and bail out if no message was received. For STATUS phase,
preserve the existing status code unless a new value was transferred.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
Link: https://lore.kernel.org/r/52e02a8812ae1a2d810d7f9f7fd800c3ccc320c4.1723001788.git.fthain@linux-m68k.org


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