Store the maximum MSIX capability in PCIe config. space earlier.  When
we call firmware to query capability, we need to compare the PCIe
MSIX max count with the firmware count and use the smaller one as
the MSIX count for 57500 (P5) chips.

The new chips don't use ring groups.  But previous chips do and
the existing logic limits the available rings based on resource
calculations including ring groups.  Setting the max ring groups to
the max rx rings will work on the new chips without changing the
existing logic.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>