msm: ipa: fix a race condition in teardown pipe

Starting IPA 4.0 a pipe cannot be suspended. Instead the GSI
channel needs to be stopped. This change moves the GSI stop
to the same place where pipe suspend used to be.

Change-Id: I5b7f2301490cf45f6f02c4ede84a75925b381e6e
CRs-Fixed: 2244241
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>