powerpc/pseries: Support lower minimum entitlement for virtual processors

This patch changes the architecture vector to advertise support for a
lower minimum virtual processor entitled capacity.  The default
minimum without this patch is 10%, this patch specifies 1%.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>