ARM: dts: msm: Update MHI configuration for sm8150

Based on client's requirements, update MHI configurations
to disable automatic buffer allocation for DIAG, start
IPCR channels automatically after probe, and enable automatic
buffer allocations for IP_CTRL channel.

CRs-Fixed: 2239849
Change-Id: I1fa145faaddbcfce6ddbf171fc76f3afe76b8952
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>