mhi: core: enable doorbell method for time synchronization

Some devices support doorbell method to collect time
synchronization information. Add support from host for the
updated way of handling initialization and advertising
support.

Change-Id: I5bc82b946fd64927a2a88babc8d383e5fa664cf6
Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>