qed: IGU read revised

As a first step for relaxing various assumptions done by driver
about the IGU mapping, the driver is now going to read the entire
IGU into a shadow copy, and mark in its database each status block
that's relevant for it.

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>