Draft: Add GUIDs needed for edk2 BlSMMStoreDxe
9elements' BlSMMStoreDxe in edk2 uses these GUIDs to implement UEFI variable support when using SMMSTOREv2 in coreboot. Tools such as System76 firmware-update will need this to parse the firmware volume.
Values taken from edk2.
EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL_GUIDEFI_SYSTEM_NV_DATA_FV_GUIDEFI_AUTHENTICATED_VARIABLE_GUIDEFI_VARIABLE_GUID