i40e: fix up scanf decoders

Fix up a couple of scanfs to accept various base numbers instead of silently
requiring hex.

Change-Id: I1cc4dffbb1d011bf603cbf34a8db093da57fad7a
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>