scsi: hpsa: fix an uninitialized read and dereference of pointer dev

Currently the check for a lockup_detected failure exits via the label
return_reset_status that reads and dereferences an uninitialized pointer
dev.  Fix this by ensuring dev is inintialized to null.

Addresses-Coverity: ("Uninitialized pointer read")
Fixes: 14991a5bade5 ("scsi: hpsa: correct device resets")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Don Brace <don.brace@microsemi.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>