Kernel: Simplify dump_backtrace() API for clients.

It makes no sense that clients had to worry about whether or not KSyms
were loaded.

Kernel/Process.cpp

@@ -642,7 +642,7 @@ void Process::sys$exit(int status)
     kprintf("sys$exit: %s(%u) exit with status %d\n", name().characters(), pid(), status);
 #endif
 
-    dump_backtrace(ksyms_ready);
+    dump_backtrace();
 
     m_termination_status = status;
     m_termination_signal = 0;