net: ethtool: avoid OOB accesses in PAUSE_SET

We now reuse .parse_request() from GET on SET, so we need to make sure
that the policies for both cover the attributes used for .parse_request().
genetlink will only allocate space in info->attrs for ARRAY_SIZE(policy).

Reported-by:  <syzbot+430f9f76633641a62217@syzkaller.appspotmail.com>
Fixes: 963781bd ("net: ethtool: call .parse_request for SET handlers")
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250626233926.199801-1-kuba@kernel.org


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