scsi: core: Improve the code for showing commands in debugfs

scsi: core: Improve the code for showing commands in debugfs

Some but not all command information is cleared by scsi_end_request().
As an example, if scsi_show_rq() is called after a SCSI command has been
allocated and before SCMD_INITIALIZED is set, .cmnd holds the CDB
of a previous command. Showing that information in debugfs is confusing.
Hence this patch that restricts the information shown in debugfs to
valid information.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240325224755.1477910-3-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>