i40e: clean up error status messages

Clean up a little confusion in reporting error status in phy and fcoe
setup error reports by separating the return status from the AQ error.

Add two decoder functions to make this easier.

Change-ID: I960bcdeef3978a15fec1cdb5eff781d5cbae42fb
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Jim Young <james.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>