kmod/core: add support for R_X86_64_64 dynrelas

Needed for relocations to data sections.
create-diff-object: include relas for non-bundled sections

With test/integration/data-read-mostly.patch, create-diff-object
includes the __verbose section but not the .rela__verbose section, which
is a bug, resulting in the following printk during the integration
tests:

  [13740.801920] dynamic debug error adding module: (null)

If a non-bundled section is included, its rela section should also be
included.  Also add support for converting those relas to dynrelas.