The rsu firmware license check has been disabled since r292756. Changes
rsu(4) since the license ack is no longer required.
While here, add `device rsufw` hint to the kernel configuration lines and
add/update paths to the installed license file in both rsu(4) and rsufw(4).
Submitted by: Mateusz Piotrowski (0mp)
Reviewed by: bcr (manpages)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D14966