clover: Reduce wait_count in abort path.

Trigger waiter condition variable.
Passes 'events' CTS on carrizo and turks.
v2: reduce to 0

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
(cherry picked from commit 1e8b8e08)