media.log cleanup

Remove almost all of the specific logs, but leave the media.log
logging infrastructure in place for the next time we need it.

Re-apply a few good changes that were reverted earlier:
 - check logf format vs. argument list compatibility
 - distinguish potentially modified and actually modified tracks in FastMixer
 - fix benign bug where sq->end() was called more than once
 - fix a build warning

Bug: 6490974
Change-Id: I02d3e83646c738acaebb415bd0d6b548638b4ef5
diff --git a/services/audioflinger/Threads.h b/services/audioflinger/Threads.h
index fa1e336..4595b6c 100644
--- a/services/audioflinger/Threads.h
+++ b/services/audioflinger/Threads.h
@@ -315,7 +315,7 @@
                 // keyed by session ID, the second by type UUID timeLow field
                 KeyedVector< int, KeyedVector< int, sp<SuspendedSessionDesc> > >
                                         mSuspendedSessions;
-                static const size_t     kLogSize = 512;
+                static const size_t     kLogSize = 4 * 1024;
                 sp<NBLog::Writer>       mNBLogWriter;
 };
 
@@ -546,7 +546,7 @@
     sp<NBAIO_Sink>          mTeeSink;
     sp<NBAIO_Source>        mTeeSource;
     uint32_t                mScreenState;   // cached copy of gScreenState
-    static const size_t     kFastMixerLogSize = 8 * 1024;
+    static const size_t     kFastMixerLogSize = 4 * 1024;
     sp<NBLog::Writer>       mFastMixerNBLogWriter;
 public:
     virtual     bool        hasFastMixer() const = 0;