mbuf: Add sysctl flag CTLFLAG_TUN to loader tunables
The following sysctl variables are actually loader tunables. Add sysctl
flag CTLFLAG_TUN to them so that sysctl -T will report them correctly.
- kern.ipc.mb_use_ext_pgs
- kern.ipc.nmbclusters
- kern.ipc.nmbjumbop
- kern.ipc.nmbjumbo9
- kern.ipc.nmbjumbo16
- kern.ipc.nmbufs
No functional change intended.
Reviewed by: kib, imp
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D42113
(cherry picked from commit 6a88498e53b24d870e066c2a94910ad23dd355eb)