msm: pm: bug in pc debug counters logic

The logic to find the location to add debug counter
for a CPU is incorrect and due to this the counter
of next CPU is corrupted. The logic is updated to
correct this.

CRs-fixed: 596773
Change-Id: I6de21bd480720d80ad9801d8a1331b6faf689b95
Signed-off-by: Anil kumar mamidala <amami@codeaurora.org>