ice: support for GRE in eswitch

ice: support for GRE in eswitch

Mostly reuse code from Geneve and VXLAN in TC parsing code. Add new GRE
header to match on correct fields. Create new dummy packets with GRE
fields.

Instead of checking if any encap values are presented in TC flower,
check if device is tunnel type or redirect is to tunnel device. This
will allow adding all combination of rules. For example filters only
with inner fields.

Return error in case device isn't tunnel but encap values are presented.

gre example:
- create tunnel device
ip l add $NVGRE_DEV type gretap remote $NVGRE_REM_IP local $VF1_IP \
dev $PF
- add tc filter (in switchdev mode)
tc filter add dev $NVGRE_DEV protocol ip parent ffff: flower dst_ip \
$NVGRE1_IP action mirred egress redirect dev $VF1_PR

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>