First stages of a module dependency cleanup. This part fixes a

First stages of a module dependency cleanup.  This part fixes a
particularly annoying hack, namely having the linker bash the moduledata
to set the container pointer, preventing it being const.  In the process,
a stack of warnings were fixed and will probably allow a revisit of the
const C_SYSINIT() changes.  This explicitly registers modules in files or
preload areas with the module system first, and let them initialize via
SYSINIT/DECLARE_MODULE later in their SI_ORDER_xxx order.  The kludge of
finding the containing file is no longer needed since the registration
of modules onto the modules list is done in the context of initializing
the linker file.