net/ice/base: support switch for IPv6 TC field

net/ice/base: support switch for IPv6 TC field

Add support for IPv6 traffic class (tc) field for switch rule.
Correct ice_ipv6_hdr based on the IPv6 Protocol using bitfields.
Add big/little endian convert for tc field before it is inserted,
since tc is only one byte and also does not have a byte-aligned
offset.

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>