vmwgfx: Make vmw_wait_seqno a bit more readable

Break out on-demand enabling and disabling of fence irqs to make
the function more readable. Also make dev_priv->fence_queue_waiters an int
instead of an atomic_t since we only manipulate it with dev_priv->hw_mutex
held.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 9c3016b..3018871 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -241,7 +241,7 @@
 	atomic_t marker_seq;
 	wait_queue_head_t fence_queue;
 	wait_queue_head_t fifo_queue;
-	atomic_t fence_queue_waiters;
+	int fence_queue_waiters; /* Protected by hw_mutex */
 	atomic_t fifo_queue_waiters;
 	uint32_t last_read_seqno;
 	spinlock_t irq_lock;