llkd: Add waiting task to dump

Consider reporting d (lock dump) and w (waiting tasks) after
t (stack dump) as the ramoops buffer could be overflowed.

Test: compile
Bug: 118712403
Change-Id: I64fac7e13c14a1cbc45c9e35fe7746f9b778dcf4
diff --git a/llkd/libllkd.cpp b/llkd/libllkd.cpp
index eec3f90..7140c3b 100644
--- a/llkd/libllkd.cpp
+++ b/llkd/libllkd.cpp
@@ -524,10 +524,16 @@
     if (dump) {
         // Show all locks that are held
         android::base::WriteStringToFd("d", sysrqTriggerFd);
+        // Show all waiting tasks
+        android::base::WriteStringToFd("w", sysrqTriggerFd);
         // This can trigger hardware watchdog, that is somewhat _ok_.
         // But useless if pstore configured for <256KB, low ram devices ...
         if (llkEnableSysrqT) {
             android::base::WriteStringToFd("t", sysrqTriggerFd);
+            // Show all locks that are held (in case 't' overflows ramoops)
+            android::base::WriteStringToFd("d", sysrqTriggerFd);
+            // Show all waiting tasks (in case 't' overflows ramoops)
+            android::base::WriteStringToFd("w", sysrqTriggerFd);
         }
         ::usleep(200000);  // let everything settle
     }