SapImpl: log error description

Test: pass
Bug: 35937742
Change-Id: I9784a15d8de5dc8a0bff849d5d3ef8c162bcb1a0
diff --git a/libril/sap_service.cpp b/libril/sap_service.cpp
index 81b04c9..29c2f38 100644
--- a/libril/sap_service.cpp
+++ b/libril/sap_service.cpp
@@ -76,7 +76,8 @@
 
 void SapImpl::checkReturnStatus(Return<void>& ret) {
     if (ret.isOk() == false) {
-        RLOGE("checkReturnStatus: unable to call response/indication callback");
+        RLOGE("checkReturnStatus: unable to call response/indication callback: %s",
+                ret.description().c_str());
         // Remote process (SapRilReceiver.java) hosting the callback must be dead. Reset the
         // callback object; there's no other recovery to be done here. When the client process is
         // back up, it will call setCallback()