ARM: dts: msm: Enable low power mode in sdmsrhirke

By default, Low Power Mode (LPM) should be enabled, lack of
which causes non-zero RBSC - Rock Bottom Sleep Current
values.

Change-Id: I06b18c3f7ebe3154666f49e796bb4c12e0f11b9f
Signed-off-by: Anjana Hari <ahari@codeaurora.org>