ixgbe: Add support to retrieve and store LED link active

This patch adds support to get the LED link active via the LEDCTL
register.  If the LEDCTL register does not have LED link active
(LED mode field = 0x0100) set then default LED link active returned.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>