net: aquantia: Improve link state and statistics check interval callback

Reduce timeout from 2 secs to 1 sec. If link is down,
reduce it to 500msec. This speeds up link detection.

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