chtls: Convert to skb_dst_reset

Going forward skb_dst_set will assert that skb dst_entry
is empty during skb_dst_set. skb_dstref_steal is added to reset
existing entry without doing refcnt. Chelsio driver is
doing extra dst management via skb_dst_set(NULL). Replace
these calls with skb_dstref_steal.

Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250818154032.3173645-7-sdf@fomichev.me


Signed-off-by: Jakub Kicinski <kuba@kernel.org>