net: use indirect call helpers for dst_output

[ Upstream commit 6585d7dc ]

This patch avoids the indirect call for the common case:
ip6_output and ip_output

Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 13e55fba ("net: ipv6: fix dst ref loop on input in rpl lwt")
Signed-off-by: Sasha Levin <sashal@kernel.org>