Docs: fix typos

Original patch from
https://github.com/scottwedge/perfetto/commit/0b6e31898fa8f53b377e9495770ae0814bf17dc2

Change-Id: I6f30f7ee7c21eb5f7615b91e5ba898b70bfe13f5
diff --git a/include/README.md b/include/README.md
index 6edb3ca..3be92c4 100644
--- a/include/README.md
+++ b/include/README.md
@@ -103,7 +103,7 @@
   });
 ```
 
-The passed labmda will be called only if tracing is enabled and the data source
+The passed lambda will be called only if tracing is enabled and the data source
 was enabled in the trace config. It might be called multiple times, one for each
 active tracing session, in case of concurrent tracing sessions (or even within a
 single tracing session, if the data source is listed twice in the trace config).