gitignore generated out directory

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/.gitignore b/.gitignore
index 1588816..6b4c411 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,4 @@
 *.swp
 *.ta
 cscope.*
+out/