[bssl] Move ec_key module from rialto to libbssl

Bug: 301068421
Test: atest rialto_test
Change-Id: I04f3040f79f1af18b5c76546adcd6616aa052729
diff --git a/rialto/src/requests/rkp.rs b/rialto/src/requests/rkp.rs
index bcddf67..6982337 100644
--- a/rialto/src/requests/rkp.rs
+++ b/rialto/src/requests/rkp.rs
@@ -15,11 +15,11 @@
 //! This module contains functions related to the attestation of the
 //! service VM via the RKP (Remote Key Provisioning) server.
 
-use super::ec_key::EcKey;
 use super::pub_key::{build_maced_public_key, validate_public_key};
 use alloc::string::String;
 use alloc::vec;
 use alloc::vec::Vec;
+use bssl_avf::EcKey;
 use ciborium::{cbor, value::Value};
 use core::result;
 use coset::{iana, AsCborValue, CoseSign1, CoseSign1Builder, HeaderBuilder};