Fix dynamic ro.sf.lcd_density being ignored

On Qualcomm devices, ro.sf.lcd_density is set by a shell script in
/vendor, which will be called after surfaceflinger is started.
Thus surfaceflinger won't read any value, and will consider the default
value which is 213.

To fix this, restart surfaceflinger when ro.sf.lcd_density is changed.

vndk.rc

@@ -44,3 +44,5 @@ on property:persist.sys.phh.caf.audio_policy=*
 on property:persist.sys.phh.vsmart.dt2w=*
     exec u:r:phhsu_daemon:s0 root -- /system/bin/phh-prop-handler.sh "persist.sys.phh.vsmart.dt2w"
 
+on property:ro.sf.lcd_density=*
+    restart surfacecflinger