The Scheduled Process Area is allocated dynamically with enough pages to
fit at least as many processes as the AFU descriptor indicated. Since
the calculation is non-trivial, it does this by calculating how many
processes could fit in an allocation of a given order, and increasing
that order until it can fit enough processes or hits the maximum
supported size.

Currently, it will start this search using a SPA of 2 pages instead of
1. This can waste a page of memory if the AFU's maximum number of
supported processes was small enough to fit in one page.

Fix the algorithm to start the search at 1 page.
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>