nfp: double free on error in probe

Both the nfp_net_pf_app_start() and the nfp_net_pci_probe() functions
call nfp_net_pf_app_stop_ctrl(pf) so there is a double free.  The free
should be done from the probe function because it's allocated there so
I have removed the call from nfp_net_pf_app_start().

Fixes: 02082701 ("nfp: create control vNICs and wire up rx/tx")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>