ixgbe: add support for older QSFP active DA cables

This patch adds support for QSFP active direct attach (DA) cables which
pre-date SFF-8436 v3.6.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>