[network-data] remove redudnant code from RegisterNetworkData() (#4562)
[network-data] remove redudnant code from RegisterNetworkData() (#4562)

chshu/openthread,openthread/openthread,lanyuwen/openthread,chshu/openthread,librasungirl/openthread,chshu/openthread,bukepo/openthread,jwhui/openthread,librasungirl/openthread,openthread/openthread,lanyuwen/openthread,lanyuwen/openthread,chshu/openthread,bukepo/openthread,chshu/openthread,jwhui/openthread,bukepo/openthread,openthread/openthread,librasungirl/openthread,bukepo/openthread,librasungirl/openthread,srickardti/openthread,chshu/openthread,abtink/openthread,abtink/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,srickardti/openthread,lanyuwen/openthread,jwhui/openthread,openthread/openthread,srickardti/openthread,abtink/openthread,lanyuwen/openthread,lanyuwen/openthread