zenfone7: Set ro.surface_flinger.use_content_detection_for_refresh_rate property to true

Change-Id: I3fb5c9c9cdfe869853ecffda4d99da3372fadb1d
diff --git a/vendor.prop b/vendor.prop
index 7181ac9..5587a08 100644
--- a/vendor.prop
+++ b/vendor.prop
@@ -219,3 +219,6 @@
 # Chipset
 ro.soc.manufacturer=QTI
 ro.soc.model=SM8250
+
+# Display
+ro.surface_flinger.use_content_detection_for_refresh_rate=true