gluon-core: fix primary MAC address on TP-LINK Archer C5/C7

package/gluon-core/files/lib/gluon/upgrade/010-primary-mac

@@ -23,6 +23,10 @@ if platform.match('ar71xx', 'generic', {'tl-wdr3600', 'tl-wdr4300'}) then
   table.insert(try_files, 1, '/sys/class/ieee80211/phy1/macaddress')
 end
 
+if platform.match('ar71xx', 'generic', {'archer-c5', 'archer-c7'}) then
+  table.insert(try_files, 1, '/sys/class/net/eth1/address')
+end
+
 
 for _, file in ipairs(try_files) do
   local addr = fs.readfile(file)