i40e: fix registering XDP RxQ info

[ Upstream commit 8f497dc8a61429cc004720aa8e713743355d80cf ]

Current way of handling XDP RxQ info in i40e has a problem, where frag_size
is not updated when xsk_buff_pool is detached or when MTU is changed, this
leads to growing tail always failing for multi-buffer packets.

Couple XDP RxQ info registering with buffer allocations and unregistering
with cleaning the ring.

Fixes: a045d2f2d03d ("i40e: set xdp_rxq_info::frag_size")
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Link: https://patch.msgid.link/20260305111253.2317394-6-larysa.zaremba@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>