net/ncsi: Silence runtime memcpy() false positive warning

net/ncsi: Silence runtime memcpy() false positive warning

The memcpy() in ncsi_cmd_handler_oem deserializes nca->data into a
flexible array structure that overlapping with non-flex-array members
(mfr_id) intentionally. Since the mem_to_flex() API is not finished,
temporarily silence this warning, since it is a false positive, using
unsafe_memcpy().

Reported-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/netdev/CACPK8Xdfi=OJKP0x0D1w87fQeFZ4A2DP2qzGCRcuVbpU-9=4sQ@mail.gmail.com/
Cc: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221202212418.never.837-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>