Fix issue 1999585: audioflinger crash.

We were looping on the number of playback threads when dumping record threads.
diff --git a/libs/audioflinger/AudioFlinger.cpp b/libs/audioflinger/AudioFlinger.cpp
index bc0854e..1336131 100644
--- a/libs/audioflinger/AudioFlinger.cpp
+++ b/libs/audioflinger/AudioFlinger.cpp
@@ -235,7 +235,7 @@
         }
 
         // dump record threads
-        for (size_t i = 0; i < mPlaybackThreads.size(); i++) {
+        for (size_t i = 0; i < mRecordThreads.size(); i++) {
             mRecordThreads[i]->dump(fd, args);
         }