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.  In the common case, most allocations will be
less than a page and those uses kmalloc.  Therefore, for the majority
of situations, this will have no impact.

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