multimedia/libhdhomerun: Backport FreeBSD broadcast patch

Release 20190621 caused a regression in the ability to discover tuner
hardware, for example using: hdhomerun_config discover.

This change backports a commit [1] marked as "Release 20190625" which
doesn't (yet?) appear to be available/distributed.

[1] https://github.com/Silicondust/libhdhomerun/commit/b0e5d5f5c8e2bf37dea34beb014e08ebb598ebf6

PR: 240907
Reported by: Daniel Becker <razzfazz gmail com>
Submitted by: David O'Rourke <dor.bsd xm0 uk> (maintainer)