kconfig: update compression algorithm info

There have been new compression algorithms added without updating nearby
relevant descriptive text that refers to (a) the number of compression
algorithms and (b) the most recent one.  Fix these inconsistencies.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Reported-by:  <qasdfgtyuiop@gmail.com>
Cc: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>