msm: ipa3: implement GSI stop channel sequence

Add a new API to stop a GSI channel in IPA.
Due to a HW limitation, a special handling is needed in case
first attempt of stopping a GSI channel results in STOP_IN_PROG state.

Change-Id: Ieeaf7081de0faf7cbeb20dec919ef336fa931fce
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>