drm/radeon/kms: accept slightly overclocked power modes

Fixes fdo bug #26329

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Tested-by: Tobias Jakobi <liquid.acid@gmx.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 9f35bee..350ae71 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -662,6 +662,11 @@
 	bool voltage_drop_active;
 };
 
+/*
+ * Some modes are overclocked by very low value, accept them
+ */
+#define RADEON_MODE_OVERCLOCK_MARGIN 500 /* 5 MHz */
+
 struct radeon_pm {
 	struct mutex		mutex;
 	struct delayed_work	idle_work;