net: aquantia: link status irq handling

Here we define and request an extra interrupt line,
assign it on link isr handler and restructure abit aq_pci code
to better support that.

We also remove logic for using different timer intervals
depending on link state, since thats now useless.

Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>