kgdb: Fix kernel-doc format error in kgdb.h

linux-next-20081022//include/linux/kgdb.h:308): duplicate section name 'Description'

and fix typos in that file's kernel-doc comments.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>