mhi: core: timeout if sync power up fails to enter mission mode

When sync power up API is called, it does an asynchronous
attempt to power up with a timeout for mission mode entry.
If unable to enter mission mode in time, return -ETIMEDOUT
to clients so they can perform necessary clean-up actions.

Change-Id: I9f6dfcd1f287ae0c41e3dd39298fc4253d11a6da
Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>