net: remove '__' from __skb_flow_get_ports()

Only one version of skb_flow_get_ports() exists after the previous commit,
so let's remove the useless '__'.

Suggested-by: Simon Horman <horms@kernel.org>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://patch.msgid.link/20250221110941.2041629-3-nicolas.dichtel@6wind.com


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