efi: dmi: add support for SMBIOS 3.0 UEFI configuration table

efi: dmi: add support for SMBIOS 3.0 UEFI configuration table

This adds support to the UEFI side for detecting the presence of
a SMBIOS 3.0 64-bit entry point. This allows the actual SMBIOS
structure table to reside at a physical offset over 4 GB, which
cannot be supported by the legacy SMBIOS 32-bit entry point.

Since the firmware can legally provide both entry points, store
the SMBIOS 3.0 entry point in a separate variable, and let the
DMI decoding layer decide which one will be used.

Tested-by: Suravee Suthikulpanit <[email protected]>
Acked-by: Leif Lindholm <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>