msm: ipa3: fix ipa3_stop_gsi_channel active clients handling

ipa3_stop_gsi_channel() does not perform active clients reference count
decrease at function exit sequence as it should. This change fixes this
issue.

Change-Id: I8ac1dc05b1f075367bd450d0c04373f29f5e72ad
Signed-off-by: Amir Levy <alevy@codeaurora.org>