Correct display of bhyve SMBIOS UUIDs with dmidecode by bumping the version.

The mixed little/big-endianness of SMBIOS UUIDs was clarified in v2.6
of the SMBIOS spec. dmidecode uses the reported version of SMBIOS to
determine the layout and what to byte-swap.

bhyve's SMBIOS reported as 2.4 though it implemented the 2.6-style of
memory layout. This resulted in dmidecode reporting a different
UUID than one passed in via the -U option.

Fix by exporting a version of 2.6.

Reviewed by: tychon
Reported by: julian
MFC after: 1 day