ixgbe: fix build when DEBUG is defined

The ixgbe driver had issues when DEBUG was defined because the hw_dbg macro
was incomplete.  This patch completes the code based off of the code that
already existed in the igb module.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>