libril: Fix Const-Correctness for
 RIL_RadioFunctions

Re-add constant for function pointer table to
RIL_RadioFunctions. Const was accidentally removed
during a warnings cleanup.

Bug: 64231560
Test: compilation
Change-Id: I93675980c51d9162f624495d12fe3c97f1da8031
diff --git a/ril/libril/ril.cpp b/ril/libril/ril.cpp
index a6cac4a..78acd36 100644
--- a/ril/libril/ril.cpp
+++ b/ril/libril/ril.cpp
@@ -488,10 +488,10 @@
 }
 
 extern "C" void
-RIL_register_socket (RIL_RadioFunctions *(*Init)(const struct RIL_Env *, int, char **),
+RIL_register_socket (const RIL_RadioFunctions *(*Init)(const struct RIL_Env *, int, char **),
         RIL_SOCKET_TYPE socketType, int argc, char **argv) {
 
-    RIL_RadioFunctions* UimFuncs = NULL;
+    const RIL_RadioFunctions* UimFuncs = NULL;
 
     if(Init) {
         UimFuncs = Init(&RilSapSocket::uimRilEnv, argc, argv);