ixgbe: Check link wants report current link state

ixgbe: Check link wants report current link state

Currently check link reports the link state as down, if at any time
the link had previously gone down since the last time the LINKS
register was read.  This does not accurately reflect the function of
the check link call, which should be to return the CURRENT link
state. Code now reads the LINKS registers twice, once to clear the
previous and again to get the current value.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>