ARM: dts: msm: Add npu mailbox controller support for lito

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: I1b779ae0ddf98149f0792a13144069695f29bc1e