overlay: Fix crash due to small debug buffer size

The debug buffer size is insufficient for newer targets with multiple
pipes. The code causing crash is enabled only if the PIPE_DEBUG macro
is enabled during local debugging.

We now increase the buffer size and also put some string operations under
the macro check for efficiency.

Change-Id: I4ad418d314fd8c7d374ccfdb0943dde44d968922
diff --git a/liboverlay/overlay.h b/liboverlay/overlay.h
index cfceaff..3064c6a 100644
--- a/liboverlay/overlay.h
+++ b/liboverlay/overlay.h
@@ -153,7 +153,7 @@
     PipeBook mPipeBook[utils::OV_INVALID]; //Used as max
 
     /* Dump string */
-    char mDumpStr[256];
+    char mDumpStr[1024];
 
     /* Singleton Instance*/
     static Overlay *sInstance;