MFC r303848

Repair trivial panic in ng_uncallout. Fixes bugzilla #211031

PR: 211031

MFC r309404:
Fix return value from ng_uncallout().

callout_stop() recently started returning -1 when the callout is already
stopped, which is not handled by the netgraph code. Properly filter
the return value. Netgraph callers only want to know if the callout
was cancelled and not draining or already stopped.

Discussed with: julian, glebius

MFH: r278640

Revise default limit for maximum of netgraph data items.
With modern internet speeds the limit can be reached even
on a single L2TP link.

MFC r263710, r273377, r273378, r273423 and r273455:

- De-vnet hash sizes and hash masks.
- Fix multiple issues related to arguments passed to SYSCTL macros.

Sponsored by: Mellanox Technologies

Merge r260046: Fix the parse type for NGM_LISTTYPES.

MFC r263710, r273377, r273378, r273423 and r273455:

- De-vnet hash sizes and hash masks.
- Fix multiple issues related to arguments passed to SYSCTL macros.

Sponsored by: Mellanox Technologies

Merge r260046: Fix the parse type for NGM_LISTTYPES.