bnx2x: Correct EEE statistics gathering

In boards with 4-ports, Tx LPI statistics were gathered incorrectly.
This patch guarantees that each pmf will only query its own port for
these statistics.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>