bnx2x: Fix the maximal values of coalescing timeouts.

This patch properly defines the maximum values for rx/tx coalescing timeouts.

Signed-off-by: Vlad Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>