drm/amdkfd: Fix dqm->queue_count tracking

dqm->queue_count tracks queues in the active state only. In a few
places this count is modified unconditionally, leading to an incorrect
value when the UPDATE_QUEUE ioctl is used to make a queue inactive.

Signed-off-by: Jay Cornwall <jay.cornwall@amd.com>
Reviewed-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>