MFC: r208778

• Mention that VTOC8 labels are found in Fujitsu SPARC64 machines as well.
• Add information regarding VTOC8 bootrstrap code and how it's handled with r208777 in place.
• Document the mapping of partition types to VTOC8 tags.
• Add examples for VTOC8 to the respective section.
• Eliminated hard sentence breaks.

Reviewed by: marcel (slightly buggy version)