i40e: properly parse MDET registers

Fix a few problems with our parsing of the MDET registers:
* Queue IDs are longer than 8 bits
* Queue IDs are absolute for the device and the base queue must be
  subtracted out.
* VF IDs are longer than 8 bits
* Use the MASK define to mask the event value, instead of the SHIFT
  define.

Change-ID: I3dc7237f480c02e1192a2a8ea782f8a02ab2a8b7
Reported-by: Marc Neustadter <marc.neustadter@intel.com>
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Patrick Lu <patrick.lu@intel.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>