spelling: s/retreive/retrieve/

Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 98e9f05..81567e9 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -438,7 +438,7 @@
 
 	/*
 	 * Fill the ppc64_caches & systemcfg structures with informations
-	 * retreived from the device-tree. Need to be called before
+	 * retrieved from the device-tree. Need to be called before
 	 * finish_device_tree() since the later requires some of the
 	 * informations filled up here to properly parse the interrupt
 	 * tree.