cxgb4vf: Add 40G support for cxgb4vf driver

Add 40G support for cxgb4vf driver. ethtool speed values are just numbers of
megabits and there is no SPEED_40000 in ethtool speed values. To be consistent,
use integer constants directly for all speeds.

Use is_x_10g_port()("is 10Gb/s or higher") in cfg_queues() instead of
is_10g_port() ("is exactly 10Gb/s"). Else we will end up using a single
"Queue Set" on 40Gb/s adapters.

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>