x86: UV: BAU partition-relative distribution map

This patch enables each partition's BAU distribution bit map
to be partition-relative.

The distribution bitmap had been constructed assuming 0 as the base
node number.  That construct would not have allowed a total system of
greater than 256 nodes.
It also corrects an error that occurred when the first blade's nasid
was not zero.  That nasid was stored as the base node.
The base node number gets added by hardware to the node numbers implied
in the distribution bitmap, resulting in invalid target nasids.

Tested on the UV hardware simulator.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
LKML-Reference: <E1Ltl0C-0004Ob-37@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>