Cell OProfile: Incorrect local array size in activate spu profiling function

The size of the pm_signal_local array should be equal to the
number of SPUs being configured in the call.  Currently, the
array is of size 4 (NR_PHYS_CTRS) but being indexed by a for
loop from 0 to 7 (NUM_SPUS_PER_NODE).

Signed-off-by: Carl Love <carll@us.ibm.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>