Documentation: HFS is orphaned

Removed the reference of Roman Zippel, last maintainer, of orphaned
HFS filesystem.

Signed-off-by: Marcos Paulo de Souza <marcos.mage@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>