.gitignore: Add /SPL

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
diff --git a/.gitignore b/.gitignore
index be09894..bff721e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,7 @@
 #
 
 /MLO
+/SPL
 /System.map
 /u-boot
 /u-boot.hex