[PATCH] Doc: vm/hugetlbpage update-2

Add new line of /proc/meminfo output.

Explain the HugePage_ lines in /proc/meminfo (from Bill Irwin).

Change KB to kB since the latter is what is used in the kernel.

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>