flow: Always inline miniflows.

flow: Always inline miniflows.

Now that performance critical code already inlines miniflows and
minimasks, we can simplify struct miniflow by always dynamically
allocating miniflows and minimasks to the correct size.  This changes
the struct minimatch to always contain pointers to its miniflow and
minimask.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>