[BNX2]: Possible sparse fixes, take two

This patch contains the following possible cleanups/fixes:

- use C99 struct initializers
- make a few arrays and structs static
- remove a few uses of literal 0 as NULL pointer
- use convenience function instead of cast+dereference in bnx2_ioctl()
- remove superfluous casts to u8 * in calls to readl/writel

Signed-off-by: Peter Hagervall <hager@cs.umu.se>
Acked-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>