scsi: core: Stop using DRIVER_ERROR

Return the actual error code in __scsi_execute() (which, according to the
documentation, should have happened anyway).  And audit all callers to cope
with negative return values from __scsi_execute() and friends.

[mkp: resolve conflict and return bool]

Link: https://lore.kernel.org/r/20210427083046.31620-7-hare@suse.de


Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>