ipv6: mcast: annotate data-race around psf->sf_count[MCAST_XXX]

psf->sf_count[MCAST_XXX] fields are read locklessly from
ipv6_chk_mcast_addr() and igmp6_mcf_seq_show().

Add READ_ONCE() and WRITE_ONCE() annotations accordingly.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20241210183352.86530-4-edumazet@google.com


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