ldd3: Linux Device Drivers 3 examples updated to work with recent kernels

About
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Linux Device Drivers 3 (http://lwn.net/Kernel/LDD3/) book is now a few years
old and most of the example drivers do not compile in recent kernels.
Also, many new changes were introduced in the kernel since version 2.6.10.
Examples for many ABIs are not covered in the book, like netlink sockets,
threaded interrupt handlers, debugfs, etc.

This project aims to keep LDD3 example drivers up-to-date with recent kernels.

The original code can be found at: http://examples.oreilly.com/9780596005900/

Besides the original drivers, there is a plan to add more examples that cover
more recent kernel features like the listed before.