SSC MODE SELECT: Correctly determine MODE PAGE size

Read MODE data from initiator before using fields to calculating
mode page & mode page size

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
Signed-off-by: Mark Harvey <markh794@gmail.com>
SSC MODE SELECT: Improve log message

- Improve logging message readability
- Add t10.org reference to comment regarding several fields

Signed-off-by: Sebastian Herbszt <herbszt@gmx.de>
Signed-off-by: Mark Harvey <markh794@gmail.com>