net: systemport: Support 64bit statistics

When using Broadcom Systemport device in 32bit Platform, ifconfig can
only report up to 4G tx,rx status, which will be wrapped to 0 when the
number of incoming or outgoing packets exceeds 4G, only taking
around 2 hours in busy network environment (such as streaming).
Therefore, it makes hard for network diagnostic tool to get reliable
statistical result, so the patch is used to add 64bit support for
Broadcom Systemport device in 32bit Platform.

This patch provides 64bit statistics capability on both ethtool and ifconfig.

Signed-off-by: Jianming.qiao <kiki-good@hotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>