net: prepare for non devmem TCP memory providers

There is a good bunch of places in generic paths assuming that the only
page pool memory provider is devmem TCP. As we want to reuse the net_iov
and provider infrastructure, we need to patch it up and explicitly check
the provider type when we branch into devmem TCP code.

Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://patch.msgid.link/20250204215622.695511-9-dw@davidwei.uk


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