Toward a better list iterator for the kernel

Mindlessly adding preinitializations to uninitialized variables instead of fixing the real problems prevents the compiler from flagging newly introduced uninitialized users of the same variable later.

BTW, I used to fix all newly introduced non-false positives reported by gcc-4.1.2, which was rather strict (compared to later gcc versions), and caused lots of false positives. But every kernel release, I did catch a handful of real bugs. Later, gcc improved, Arnd started to build the kernel with bleeding edge gcc versions catching more bugs before I found them, and support for gcc-4.1.2 was dropped. But I believe there still are areas for improvements...