Use String8/16 c_str [cas]

Bug: 295394788
Test: make checkbuild
Change-Id: I1faccac8711d5cccee70443548940d99804c7c2a
diff --git a/cas/1.0/default/DescramblerImpl.cpp b/cas/1.0/default/DescramblerImpl.cpp
index f79b32d..6b730eb 100644
--- a/cas/1.0/default/DescramblerImpl.cpp
+++ b/cas/1.0/default/DescramblerImpl.cpp
@@ -62,8 +62,7 @@
 }
 
 Return<Status> DescramblerImpl::setMediaCasSession(const HidlCasSessionId& sessionId) {
-    ALOGV("%s: sessionId=%s", __FUNCTION__,
-            sessionIdToString(sessionId).string());
+    ALOGV("%s: sessionId=%s", __FUNCTION__, sessionIdToString(sessionId).c_str());
 
     std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);
     if (holder.get() == nullptr) {