[HEADSUP] big polling changes

[Yuriy N. Shkandybin]

Hello.

I've tested nge and confirm that with 
        sc->nge_ldata = contigmalloc(sizeof(struct nge_list_data), M_DEVBUF,
-           M_NOWAIT, 0, 0xffffffff, PAGE_SIZE, 0);
+           M_NOWAIT|M_ZERO, 0, 0xffffffff, PAGE_SIZE, 0);

polling works.

Also want to notice interrupt load with polling enable.
CPU states:  0.0% user,  0.0% nice,  2.4% system, 26.4% interrupt, 71.2% idle
without polling.
CPU states:  1.0% user,  0.0% nice,  5.8% system,  0.0% interrupt, 93.3% idle
but same behavour i've seen since RELENG_5.

There is no such load with em driver.

If additional testing needed i can help and provide access to testbox with 7.0 and nge card.

Jura