Documentation: admin-guide: direct people to bug trackers, if specified

Update bug reporting info in bug-hunting.rst to direct people to
driver/subsystem bug trackers, if explicitly specified with the
MAINTAINERS "B:" entry. Use the new get_maintainer.pl --bug option to
print the info.

Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240815113450.3397499-2-jani.nikula@intel.com