fix typos concerning "hierarchy"

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c
index b32ccd95..ed8d330 100644
--- a/arch/arm/mach-omap2/dpll3xxx.c
+++ b/arch/arm/mach-omap2/dpll3xxx.c
@@ -463,7 +463,7 @@
 	}
 	if (!ret) {
 		/*
-		 * Switch the parent clock in the heirarchy, and make sure
+		 * Switch the parent clock in the hierarchy, and make sure
 		 * that the new parent's usecount is correct.  Note: we
 		 * enable the new parent before disabling the old to avoid
 		 * any unnecessary hardware disable->enable transitions.