PIC Resiliency: 802.3X Ethernet PAUSE autonegotiation enhancements

Enables to configure asymmetric flow control. To configure PAUSE, include both the rx-buffers and tx-buffers statements at the [edit interfaces interface-name ether-options configured-flow-control] hierarchy level. The rx-buffers statement determines whether or not the interface generates and sends PAUSE messages. The tx-buffers statement determines whether or not the interfaces responds to received PAUSE messages.