Insert an explicit cast for -Wc++11-narrowing error

with a clang/i?86 build

Signed-off-by: Ray-V <ray-v@inbox.lv>

tdehtml/ecma/kjs_proxy.cpp

@@ -387,8 +387,8 @@ void KJSCPUGuard::start(unsigned int ms, unsigned int i_ms)
 
   oldAlarmHandler = signal(SIGVTALRM, alarmHandler);
   itimerval tv = {
-      { i_ms / 1000, (i_ms % 1000) * 1000 },
-      { ms / 1000, (ms % 1000) * 1000 }
+      { static_cast<__time_t>( i_ms / 1000 ), static_cast<__suseconds_t>( (i_ms % 1000) * 1000 ) },
+      { static_cast<__time_t>( ms / 1000 ), static_cast<__suseconds_t>( (ms % 1000) * 1000 ) }
   };
   setitimer(ITIMER_VIRTUAL, &tv, &oldtv);
 }