sgx-tools/README.md: add declaration that not support DCAP driver until now
# sgx-tools
## Introduction
-`sgx-tools` is a command line tool for inclavare-containers.
+`sgx-tools` is a command line tool for inclavare-containers. **Currently `sgx-tools` can only run on the machines with [OOT SGX dirver](https://github.com/intel/linux-sgx-driver), we will support [DCAP driver](https://github.com/intel/SGXDataCenterAttestationPrimitives) as soon as possible**.
- Given the signature file of an Enclave, `sgx-tools gen-token` command can generate the corresponding token file from aesmd service.
- `sgx-tools gen-qe-target-info` command can generate Quoting Enclave's target information file from aesm service.
- Given the report file of an Enclave, a registered `SPID` of [IAS](https://api.portal.trustedservices.intel.com/EPID-attestation), `sgx-tools gen-quote` command can generate quote file from aesm service. To get the report file, you can use `rune attest` command to get you local report and save it in the report file.
