ARM: dts: msm: Enable smp2p-npu for LAGOON

This change is to enable smp2p-npu for lagoon.
The mailbox controller implemented in NPU works as a bridge
between ipcc_mproc mailbox controller and its clients. It is
required because npu driver needs to control when IPCC irq can
be sent to NPUQ6.

Change-Id: I505f123a8b1c70a6739eb657498ecbd0c8518378