Update branch names in README.txt

Change-Id: I89a74ba03e2ccade309a65a89f4ef6ee36e0e146
diff --git a/README.txt b/README.txt
index 4f29060..aa65be3 100644
--- a/README.txt
+++ b/README.txt
@@ -1,3 +1,3 @@
 The master branch in this repository is empty
 
-Please check out one of the platform specific branches, like vim2-stable or imx8mevk-stable
\ No newline at end of file
+Please check out one of the platform specific branches, like vim2 or imx8mevk
\ No newline at end of file