nfp: xsk: fix a warning when allocating rx rings

nfp: xsk: fix a warning when allocating rx rings

Previous commits introduced AF_XDP zero-copy support, in which
we need register different mem model for xdp_rxq when AF_XDP
zero-copy is enabled or not. And this should be done after xdp_rxq
info is registered, which is not needed for ctrl port, otherwise
there complaints warnings: "Missing register, driver bug".

Fix this by not registering mem model for ctrl port, just like we
don't register xdp_rxq info for ctrl port.

Fixes: 6402528b7a0b ("nfp: xsk: add AF_XDP zero-copy Rx and Tx support")
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20220309135533.10162-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>