net: page_pool: add callback for mp info printing

Add a mandatory callback that prints information about the memory
provider to netlink.

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/20250204215622.695511-7-dw@davidwei.uk


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