ice: implement GTP RSS context tracking and configuration

This commit implements the core RSS context management and configuration
logic for GTP (GTPU) protocol support in VF RSS operations.

Key implementation features:
- GTPU hash context management with pre/post processing functions
- Context index calculation and mapping for different GTPU scenarios
- Integration with main RSS configuration flow via wrapper functions
- Support for IPv4/IPv6 GTPU RSS configurations
- Rollback mechanism for handling RSS rule conflicts
- Hash context reset and cleanup functionality

The implementation provides comprehensive GTPU RSS support by:
1. Adding ice_add_rss_cfg_pre_gtpu() for preprocessing GTPU contexts
2. Adding ice_add_rss_cfg_post_gtpu() for postprocessing configurations
3. Adding ice_calc_gtpu_ctx_idx() for context index calculation
4. Integrating GTPU logic into ice_add_rss_cfg_wrap() and
   ice_rem_rss_cfg_wrap()
5. Supporting context tracking in VF hash_ctx structures

This completes the GTP RSS infrastructure enabling VFs to configure
RSS hashing on GTP-encapsulated traffic.

Co-developed-by: Dan Nowlin <[email protected]>
Signed-off-by: Dan Nowlin <[email protected]>
Co-developed-by: Jie Wang <[email protected]>
Signed-off-by: Jie Wang <[email protected]>
Co-developed-by: Junfeng Guo <[email protected]>
Signed-off-by: Junfeng Guo <[email protected]>
Co-developed-by: Qi Zhang <[email protected]>
Signed-off-by: Qi Zhang <[email protected]>
Co-developed-by: Ting Xu <[email protected]>
Signed-off-by: Ting Xu <[email protected]>
Signed-off-by: Przemek Kitszel <[email protected]>
Signed-off-by: Aleksandr Loktionov <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: aloktion