net:ethernet:aquantia: Extra spinlocks removed.

This patch removes datapath spinlocks which does not perform any
useful work.

Fixes: 6e70637f9f1e ("net: ethernet: aquantia: Add ring support code")
Signed-off-by: Pavel Belous <Pavel.Belous@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>