sfxge: Change sfxge_ev_qpoll() proto to avoid EVQ pointers array access

[arybchik]

Summary

It was the only place on data path where sc->evq array is accessed.

Sponsored by: Solarflare Communications, Inc.

Test Plan

L1D_REPLACEMENT events are measured using pmcstat under high traffic load (many streams). The patch decreases number of events.

[gnn]

Remember to add Approved by: gnn (mentor) to your commit message.

[arybchik]

Committed to head