i40e: Fix multiple link up messages

This patch addresses an issue where multiple link up messages can be logged
resulting from aq link status timing when link properties are changed (fc,
speed, etc.); solved by using a single function to handle status printing
and adding a mechanism to track whether link state (up or down) has
actually changed.

Change-ID: Ied6ed6e49dc397c77d992adc0bc9ed3767152b9d
Signed-off-by: Matt Jared <matthew.a.jared@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>