be2net: use stats-sync to read/write 64-bit stats

64-bit stats in be2net are written/read as follows using the stats-sync
interface for safe access in 32-bit archs:

64-bit 		sync			writer			reader
stats
------------------------------------------------------------------------------
tx_stats	tx_stats->sync		be_xmit			be_get_stats64,
								ethtool
tx-compl	tx_stats->sync_compl	tx-compl-processing	ethtool
rx-stats	rx_stats->sync		rx-compl-processing	be_get_stats64,
								ethtool,
								eqd-update

This patch is based on Stephen Hemminger's earlier patch on the same issue...

Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>