msm: kgsl: Decrement inflight commands on error.

If active count enable fails then the dispatch queue inflight
should be reduced along with the dispatcher inflight.

Change-Id: Id01d396cc3819b3bbc25b22cb70e72eeb5010a40
CRs-Fixed: 841989
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>