net: make page_pool_ref_netmem work with net iovs

net: make page_pool_ref_netmem work with net iovs

page_pool_ref_netmem() should work with either netmem representation, but
currently it casts to a page with netmem_to_page(), which will fail with
net iovs. Use netmem_get_pp_ref_count_ref() instead.

Fixes: 8ab79ed50cf1 ("page_pool: devmem support")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://lore.kernel.org/20250108220644.3528845-2-dw@davidwei.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>