bnx2x: Fix memory leak

There exists an `allocation race' between the CNIC and bnx2x drivers,
in which both drivers allocate the same t2 memory while disregarding a possible
previous allocation.

Additionally, due to the current order of memory releases, some of the
ILT memory in the driver is not released correctly when unloading the driver.

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>