efi_loader: provide tool to dump SMBIOS table

An EFI binary smbiosdump.efi is provided that can be used to check the
SMBIOS table for consistency and to dump it as a file.

The tool provides the following commands:

check
    Check the SMBIOS table for consistency.

exit
    Leave the tool.

help
    Show available commands.

save
    Save the SMBIOS table to a file on the EFI system partition. The file
    can be further analyzed with the dmidecode command line tool::

        dmidecode --from-dump <filename>

Specifying 'nocolor' as load option data suppresses colored output and
clearing of the screen.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>