kernel: bump 5.15 to 5.15.157

kernel: bump 5.15 to 5.15.157

Removed because they are upstream:
   generic/backport-5.15/741-v6.9-01-netfilter-flowtable-validate-pppoe-header.patch
   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=d06977b9a4109f8738bb276125eb6a0b772bc433

Removed because they are upstream:
   generic/backport-5.15/741-v6.9-02-netfilter-flowtable-incorrect-pppoe-tuple.patch
   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=e719b52d0c56989b0f3475a03a6d64f182c85b56

Manual adapted the following patches:
   generic/pending-5.15/700-netfilter-nft_flow_offload-handle-netdevice-events-f.patch
   generic/pending-5.15/723-net-mt7531-ensure-all-MACs-are-powered-down-before-r.patch
   generic/hack-5.15/650-netfilter-add-xt_FLOWOFFLOAD-target.patch

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit 84d0b0b925997f8c2d1a21a60c79f76d3070ae3e)