meta-ibm: enable persist-mac flag

-mac address wasn't persisting after reboot

Tested by:
1. Assign a valid MAC address aa:e2:84:14:28:79 to the system using
curl -k -H "X-Auth-Token:${bmc_token}" -X PATCH -D patch.txt -d '{"MACAddress":"AA:E2:84:14:28:79"}' https://$bmc/redfish/v1/Managers/bmc/EthernetInterfaces/eth0
2. Now GET and verify if the MAC address has changed using
curl -k -H "X-Auth-Token:${bmc_token}" -X GET  https://${bmc}/redfish/v1/Managers/bmc/EthernetInterfaces/eth0
3. Now reboot the BMC and verify if the MAC address remains the same

Change-Id: I334f1936f433e3e7e30ca5e669a89112f9879276
Signed-off-by: Isha Sahni <isha.sahni1@ibm.com>
diff --git a/meta-ibm/recipes-phosphor/network/phosphor-network_%.bbappend b/meta-ibm/recipes-phosphor/network/phosphor-network_%.bbappend
index eac0503..2cca900 100644
--- a/meta-ibm/recipes-phosphor/network/phosphor-network_%.bbappend
+++ b/meta-ibm/recipes-phosphor/network/phosphor-network_%.bbappend
@@ -31,6 +31,7 @@
 FILES:${PN} += "${datadir}/network/*.json"
 
 PACKAGECONFIG:append = " sync-mac"
+PACKAGECONFIG:append = " persist-mac"
 PACKAGECONFIG:append:p10bmc = " hyp-nw-config"
 
 install_network_configuration(){