imx: mxs: Fix location for the elftosb tool

The Denx FTP location is no longer reachable.

Switch to the Timesys repository instead.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
diff --git a/doc/imx/common/mxs.txt b/doc/imx/common/mxs.txt
index e23ab9c..372062c 100644
--- a/doc/imx/common/mxs.txt
+++ b/doc/imx/common/mxs.txt
@@ -57,7 +57,7 @@
 line, use:
 
 	$ VER="10.12.01"
-	$ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz
+	$ wget http://repository.timesys.com/buildsources/e/elftosb/elftosb-10.12.01/elftosb-${VER}.tar.gz
 
 Extract the file: