[ONOS-7818] Implement a device behaviour to get table statistics. Make FlowRuleDriverProvider periodically call FlowRuleProviderService.pushTableStatistics().

Change-Id: Ife2b67b8c6c3582281704afe6f9a90538afbc798
(cherry picked from commit 1e8a1bd5cef7dda8aaaa453bcd96033f79be0e98)
diff --git a/drivers/p4runtime/src/main/resources/p4runtime-drivers.xml b/drivers/p4runtime/src/main/resources/p4runtime-drivers.xml
index 7464e14..78188a7 100644
--- a/drivers/p4runtime/src/main/resources/p4runtime-drivers.xml
+++ b/drivers/p4runtime/src/main/resources/p4runtime-drivers.xml
@@ -16,6 +16,8 @@
   -->
 <drivers>
     <driver name="p4runtime" manufacturer="p4.org" hwVersion="master" swVersion="master">
+        <behaviour api="org.onosproject.net.behaviour.TableStatisticsDiscovery"
+                   impl="org.onosproject.drivers.p4runtime.P4RuntimeTableStatisticsDiscovery"/>
         <behaviour api="org.onosproject.net.device.DeviceHandshaker"
                    impl="org.onosproject.drivers.p4runtime.P4RuntimeHandshaker"/>
         <behaviour api="org.onosproject.net.packet.PacketProgrammable"