nfp: flower: fix comment typos and formatting

A number of spelling and language mistakes in the flower section are
fixed. The spacing between the text inside some comments and the comment
symbols are also updated for consistency.

Signed-off-by: Walter Heymans <walter.heymans@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>