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/include/media/nbaio/NBLog.h b/include/media/nbaio/NBLog.h
index 8fc417f..107ba66 100644
--- a/include/media/nbaio/NBLog.h
+++ b/include/media/nbaio/NBLog.h
@@ -115,7 +115,7 @@
     virtual ~Writer() { }
 
     virtual void    log(const char *string);
-    virtual void    logf(const char *fmt, ...);
+    virtual void    logf(const char *fmt, ...) __attribute__ ((format (printf, 2, 3)));
     virtual void    logvf(const char *fmt, va_list ap);
     virtual void    logTimestamp();
     virtual void    logTimestamp(const struct timespec& ts);
@@ -149,7 +149,7 @@
     LockedWriter(size_t size, void *shared);
 
     virtual void    log(const char *string);
-    virtual void    logf(const char *fmt, ...);
+    virtual void    logf(const char *fmt, ...) __attribute__ ((format (printf, 2, 3)));
     virtual void    logvf(const char *fmt, va_list ap);
     virtual void    logTimestamp();
     virtual void    logTimestamp(const struct timespec& ts);