bnxt_en: unlink page pool when stopping Rx queue

Have bnxt call page_pool_disable_direct_recycling() to unlink the old
page pool when resetting a queue prior to destroying it, instead of
touching a netdev core struct directly.

Signed-off-by: David Wei <dw@davidwei.uk>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>