ARM: dts: msm: Change MHI chan 101 config settings for mdm chipsets

Set DB_MODE preserve flag bits for MHI channel 101 to
disable resetting doorbell mode when exiting M3 state
transition.  MDM requires channel 101 doorbell mode to
be preserved.

CRs-Fixed: 1022868
Change-Id: I72394e52a4c94d30a4be77a57d0aec05b22139ee
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>