nfp: bpf: disable all ctrl vNIC capabilities

BPF firmware currently exposes IRQ moderation capability.
The driver will make use of it by default, inserting 50 usec
delay to every control message exchange.  This cuts the number
of messages per second we can exchange by almost half.

None of the other capabilities make much sense for BPF control
vNIC, either.  Disable them all.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>