net: tls: set MSG_SPLICE_PAGES consistently

We used to change the flags for the last segment, because
non-last segments had the MSG_SENDPAGE_NOTLAST flag set.
That flag is no longer a thing so remove the setting.

Since flags most likely don't have MSG_SPLICE_PAGES set
this avoids passing parts of the sg as splice and parts
as non-splice. Before commit under Fixes we'd have called
tcp_sendpage() which would add the MSG_SPLICE_PAGES.

Why this leads to trouble remains unclear but Tariq
reports hitting the WARN_ON(!sendpage_ok()) due to
page refcount of 0.

Fixes: e117dcfd

 ("tls: Inline do_tcp_sendpages()")
Reported-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/all/4c49176f-147a-4283-f1b1-32aac7b4b996@gmail.com/


Tested-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20230808180917.1243540-1-kuba@kernel.org


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