Load port led FW for Silverstone! (#4313)

Author: tiantianlv

device/celestica/x86_64-cel_silverstone-r0/led_proc_init.soc

@@ -1,2 +1,7 @@
 #The Port LED of Silverstone SONIC can't work well, after the issue is fixed by SAI, The led will start. 
 #led auto on; led start
+linkscan off
+m0 load 0 0x3800 /usr/share/sonic/platform/custom.bin
+sleep 10
+led auto on; led start
+linkscan on