cnic, bnx2x: Add CNIC_DRV_STATE_HANDLES_IRQ to ethdev->drv_state

In INTA mode, cnic and bnx2x share the same IRQ.  During chip reset,
for example, cnic will stop servicing IRQs after it has shutdown the
cnic hardware resources.  However, the shared IRQ is still active as
bnx2x needs to finish the reset.  There is a window when bnx2x does
not know that cnic is no longer handling IRQ and things don't always
work properly.

Add a flag to tell bnx2x that cnic is handling IRQ.  The flag is set
before the first cnic IRQ is expected and cleared when no more cnic
IRQs are expected, so there should be no race conditions.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>