bnx2x: Set comments according to preferred Linux style

This patch contains cosmetic changes only of restyling comments according to Linux coding standard, and add comment for get_emac_base function.
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>