[rkp] Add request/response for certificate request generation

This cl adds the request and response protocol for the
certificate request generation. It is needed by the
IRemotelyProvisionedComponent implementation in AVF.

Bug: 299256925
Test: atest rialto_test
Change-Id: I77833c24834c8e697b066dbb070b364dad626b6c
diff --git a/rialto/src/requests/api.rs b/rialto/src/requests/api.rs
index 05a386e..c4b2d8e 100644
--- a/rialto/src/requests/api.rs
+++ b/rialto/src/requests/api.rs
@@ -29,6 +29,10 @@
             let res = rkp::generate_ecdsa_p256_key_pair()?;
             Response::GenerateEcdsaP256KeyPair(res)
         }
+        Request::GenerateCertificateRequest(p) => {
+            let res = rkp::generate_certificate_request(p)?;
+            Response::GenerateCertificateRequest(res)
+        }
     };
     Ok(response)
 }