bnx2fc: Use the fcoe_sysfs control interface

This patch adds support for the new fcoe_sysfs
control interface to bnx2fc.ko. It keeps the deprecated
interface in tact and therefore either the legacy
or the new control interfaces can be used. A mixed mode
is not supported. A user must either use the new
interfaces or the old ones, but not both.

The fcoe_ctlr's link state is now driven by both the
netdev link state as well as the fcoe_ctlr_device's
enabled attribute. The link must be up and the
fcoe_ctlr_device must be enabled before the FCoE
Controller starts discovery or login.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>