efi_loader: generated SMBIOS table below 4 GiB

We currently use an outdated format 32-bit format for SMBIOS tables.
So we must allocate SMBIOS tables below 4 GiB.

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