net/ice/base: fix adding PPPoE switch rule

net/ice/base: fix adding PPPoE switch rule

Update VLAN protocol ID to correct value for single VXLAN scenario.
Fix the missing ethertype offset for PPPoE dummy packet offset to
allow matching the corresponding field.

Fixes: d1c2f76b440a ("net/ice/base: support GTP and PPPoE protocols")
Signed-off-by: Dan Nowlin <dan.nowlin@intel.com>
Signed-off-by: Junfeng Guo <junfeng.guo@intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>