Merge branch 'devlink-finish-file-split-and-get-retire-leftover-c'

Jiri Pirko says:

====================
devlink: finish file split and get retire leftover.c

This patchset finishes a move Jakub started and Moshe continued in the
past. I was planning to do this for a long time, so here it is, finally.

This patchset does not change any behaviour. It just splits leftover.c
into per-object files and do necessary changes, like declaring functions
used from other code, on the way.

The last 3 patches are pushing the rest of the code into appropriate
existing files.
====================

Link: https://lore.kernel.org/r/20230828061657.300667-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>