qed: Reset IGU CAM to default on init

The IGU CAM contains an assocaition between hardware SBs
and interrupt lines, and it can be dynamically configured
to allow more interrupts in one entity over another, specifically
for Re-distibution of SBs between a PF and its child VFs.

While we don't yet use this functionality, there are other
clients that do and as such its possible the information
passed from management firmware during initialization in
regard to the possible number of SBs doesn't accurately reflect
the current HW configuration.

The following changes are going to apply to the driver init sequence:

 a. PF is going to re-configure all entries belonging to itself and
    its child VFs in IGU CAM based on the management firmware info
    regarding the number of SBs that are supposed to exist there.

 b. PF is going to stop using the SB resource [management firmware
    provided information] for anything but the initialization.
    Instead, it would use the live-time counters it maintains for
    the numbers.

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