The kernel supports more than a single page of actions now, so userspace
should be able to take advantage of this.
Upcoming commits will completely replace this data structure but this
commit makes the bug fix clear and is suitable for cherry-picking to
long-term support branches.
The "struct odp_flow_key" used in the kernel datapath is conceptually
separate from the "flow_t" used in userspace, but until now we have
used the latter as a typedef for the former for convenience. This commit
separates them. This makes it possible in upcoming commits to change
them independently.
This is cross-ported from the "wdp" branch, which has had it for months.
