net/fm10k: redefine link status semantics

net/fm10k: redefine link status semantics

As fm10k host interface is not directly connected to PHY, marking the
link status as UP doesn't mean a lot to the application.

So, this patch basically redefines the link status as the state of
switch manager: when switch manager is running, it's LINK_UP;
when switch manager goes down by calling the fmTerminate function,
status turns to LINK_DOWN.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>