cxgb4: flower: add support for fragmentation

cxgb4: flower: add support for fragmentation

This patch adds support for matching fragmented packets in tc flower
filters.

Previously, commit 93a8540aac72 ("cxgb4: flower: validate control flags")
added a check using flow_rule_match_has_control_flags() to reject
any rules with control flags, as the driver did not support
fragmentation at that time.

Now, with this patch, support for FLOW_DIS_IS_FRAGMENT is added:
- The driver checks for control flags using
  flow_rule_is_supp_control_flags(), as recommended in
  commit d11e63119432 ("flow_offload: add control flag checking helpers").
- If the fragmentation flag is present, the driver sets `fs->val.frag` and
  `fs->mask.frag` accordingly in the filter specification.

Since fragmentation is now supported, the earlier check that rejected all
control flags (flow_rule_match_has_control_flags()) has been removed.

Signed-off-by: Harshita V Rajput <harshitha.vr@chelsio.com>
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251028075255.1391596-1-harshitha.vr@chelsio.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>