FreeBSD_HEAD_arm64 - Build #3928 - Fixed

[jenkins-admin at FreeBSD.org]

FreeBSD_HEAD_arm64 - Build #3928 - Fixed:

Build information: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/3928/
Full change log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/3928/changes
Full build log: https://jenkins.FreeBSD.org/job/FreeBSD_HEAD_arm64/3928/console

Change summaries:

305772 by andrew:
Add a missing opt_ddb.h include from places that include debug_moditor.h
to fix the build.

Obtained from:	ABT Systems Ltd
X-MFC with:	r305771
Sponsored by:	The FreeBSD Foundation