kconfig: Re-enable Docker for kernels >= v6.17-rc1
v6.17-rc1 adds commit 9fce66583f06 ("netfilter: Exclude LEGACY TABLES on PREEMPT_RT."), which disables "legacy tables" by default. This has the effect of breaking Docker, which, for Ubuntu 22.04 at least, still uses the legacy interfaces.
So let's enable CONFIG_NETFILTER_XTABLES_LEGACY in fastpath.frag to re-enable the legacy tables and bring everything back to life.
Signed-off-by: Ryan Roberts ryan.roberts@arm.com