Merge branch 'ipv6-follow-up-for-rtnl-free-rtm_newroute-series'

Kuniyuki Iwashima says:

====================
ipv6: Follow up for RTNL-free RTM_NEWROUTE series.

Patch 1 removes rcu_read_lock() in fib6_get_table().
Patch 2 removes rtnl_is_held arg for lwtunnel_valid_encap_type(), which
 was short-term fix and is no longer used.
Patch 3 fixes RCU vs GFP_KERNEL report by syzkaller.
Patch 4~7 reverts GFP_ATOMIC uses to GFP_KERNEL.

v1: https://lore.kernel.org/20250514201943.74456-1-kuniyu@amazon.com
====================

Link: https://patch.msgid.link/20250516022759.44392-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>