bnx2x: Fix link problem with some DACs

Change 2wire transfer rate of SFP+ module EEPROM from 400Khz to 100Khz
since some DACs(direct attached cables) do not work at 400Khz.

Reported-by: Krzysztof Oldzki <ole@ans.pl>
Signed-off-by: Yaniv Rosner <yanivr@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>