ixgbevf: Use cached link state instead of re-reading the value for ethtool

ixgbevf: Use cached link state instead of re-reading the value for ethtool

BugLink: https://bugs.launchpad.net/bugs/1836760
Change the ethtool link settings call to just read the cached state out of
the adapter structure instead of trying to recheck the value from the PF.
Doing this should prevent excessive reading of the mailbox.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: "Guilherme G. Piccoli" <gpiccoli@canonical.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit 1e1b0c658d9bb364b4a2a4b08a760d3e4c239bdc)
Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>