i40e: Dump the whole NVM, not half

Debugfs was reading exactly half the number of words, fix it.

Change-Id: Ieb217f3c6dca455d44e50a0dc61a6664c0cb2265
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>