mhi: mhi_qcom: Track force suspend using flags

A flag is used to track if force suspend is required.
Another flag is used to track the completion of the
force suspend. Using these flags core driver prevents
handling of bandwidth scaling event until force suspend
is completed.

Change-Id: Ifa4feae6b7f7105fb5a8973f0ab8a3fdedba182a
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>