Add SMBIOS 3.1.1 definitions
smbios 3.1.1 introduces a few additional string constants. It also more clearly defines the type 48 system management structures which aren't currently defined. In this change, we only add support for the definitions.
To test this I used four smbios images from an RA, PA, haswell, and ivy, and compared the output from smbios before and after. As expected nothing changed. As we don't have hardware with the newer definitions, it's harder to make sure we see the right thing at this moment.