Be more robust when handling Rx interrupts.  If we can't allocate a new mbuf, just discard the received frame and reuse the old mbuf. This should prevent the connection from stalling after high network traffic.
Be more robust when handling Rx interrupts.  If we can't allocate a new mbuf,
just discard the received frame and reuse the old mbuf.
This should prevent the connection from stalling after high network traffic.

MFC after:	2 weeks

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