drm/radeon: do not leave queue acquired if timeout happens in kgd_hqd_destroy()

If timeout happens, kgd_hqd_destroy() just returns -ETIME leaving queue
acquired.
It may cause a deadlock, so the patch proposes to release queue before return.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>