e1000e: consolidate two dbug macros into one simpler one

This patch depends on a previous one that cleans up redundant #includes.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>