bnx2x: Add static declaration to several functions

This patch adds static declaration to several functions in bnx2x. It eliminates
newly introduced sparse warnings reported by Fengguang Wu.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Merav Sicron <meravs@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>