kbuild: Always generate the module name automatically.

kbuild: Always generate the module name automatically.

Rusty introduced no_module_init() to provide a way of putting
the module name into a special section. People didn't like that,
and it's doable without user visible changes ;)

I didn't keep any compatibility define for no_module_init (and removed
the current occurences) in order to make sure it doesn't spread anyway.