Current URL for "Kernel API changes from 2.0 to 2.2" hasn't been available
for some time, updating. The second article about changes from 2.2 to 2.4
is missing a URL, adding it.

Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>