efi_loader: build warning in efi_tcg2_hash_log_extend_event

efi_loader: build warning in efi_tcg2_hash_log_extend_event

Building 32bit boards with the TCG2 protocol enabled leads to a build
warning due to a missing conversion.

    lib/efi_loader/efi_tcg2.c:774:27:
    error: cast to pointer from integer of different size
    [-Werror=int-to-pointer-cast]
    774 |  ret = tcg2_create_digest((u8 *)data_to_hash, data_to_hash_len,
        |                           ^

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>