datapath: Increase maximum allocation size of action list.

datapath: Increase maximum allocation size of action list.

The switch to flow based tunneling increased the size of each output
action in the flow action list.  In extreme cases, this can result
in the action list exceeding the maximum buffer size.
This doubles the maximum buffer size to compensate for the increase
in action size.
Action list is recieved from netlink callback which is allocating
linear-skb, therefore allocating another multi-page buffer would
not increase probability of the allocation-failure a lot.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Bug #15203