[POWERPC] cell: Move SPU affinity init to spu_management_of_ops

This patch moves affinity initialization code from spu_base.c to a
new spu_management_of_ops function (init_affinity), which is empty
in the case of PS3. This fixes a linking problem that was happening
when compiling for PS3.
Also, some small code style changes were made.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>