[SCSI] docbook and kernel-doc updates

- Change title to remove "Mid-Layer" since the doc is about all of the
SCSI layers.
- Use "SCSI" instead of "scsi" in docbook text.
- Use "*/" to end kernel-doc notation blocks.
- A few other minor typo fixes.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>