bnx2x: remove cast around the kmalloc in bnx2x_prev_mark_path

casting the void pointer is redundant (Documentation/CodingStyle)

Signed-off-by: Devendra Naga <develkernel412222@gmail.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>