nfp: flower: inform firmware of flower features

For backwards compatibility it may be required for the firmware to
disable certain features depending on the features supported by
the host. Combine the host feature bits and firmware feature bits
and write this back to the firmware.

Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>