Implement the "kern.disks" sysctl in GEOM.
Implement the "kern.disks" sysctl in GEOM.

This makes "mdconfig -l" work again.

Sponsored by:	DARPA & NAI Labs.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase