sm8350-common: overlay: Set preferred refresh rate on keyguard to 60

This ensures that the device doesn't switch to hrr while
doze mode is active.

Change-Id: I8488e86e56a46aea95f2835d8667c23401625f0b

overlay/frameworks/base/packages/SystemUI/res/values/config.xml

@@ -54,4 +54,7 @@
         <item>0</item>
         <item>0</item>
     </integer-array>
+
+    <!-- Preferred max refresh rate at keyguard, if supported by the display. -->
+    <integer name="config_keyguardMaxRefreshRate">60</integer>
 </resources>