ARM: dts: msm: Add QMP debugfs client on atoll

The QMP debugfs client uses the QMP mailbox driver to communicate
with the Always On processor.

Change-Id: I8f4f2d3ca9b459e52a6e93a6104bc23f5e156b99
Signed-off-by: Raghavendra Kakarla <rkakarla@codeaurora.org>