xtensa: tell git to ignore generated files

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/boot/.gitignore b/arch/xtensa/boot/.gitignore
new file mode 100644
index 0000000..38177c7
--- /dev/null
+++ b/arch/xtensa/boot/.gitignore
@@ -0,0 +1,2 @@
+uImage
+zImage.redboot