ARM: dts: msm: Allow L2 retention mode for MSM8917

We want to avoid L2PC but we want to allow L2 retention
mode. Latency for L2 retention is 650 and for L2PC
it is 11200us. Keep active latency to 651 to allow L2
retention mode.

Change-Id: I78d842151dd9193191d887049926246531ab8731
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>