Function 'netxen_rom_fast_read' is declared twice, so remove the
repeated declaration.

Cc: Manish Chopra <manishc@marvell.com>
Cc: Rahul Verma <rahulv@marvell.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>