thunderbolt: Write descriptors in tb_ring_poll()

When the ring is not in interrupt mode, it depends on something
enqueuing new frames to write the descriptors from ring->queue to the
hardware, and that can take a long time. Since we know that we just
released one slot, we can push the next frame directly from
tb_ring_poll().

Reported-by: Alan Borzeszkowski <alan.borzeszkowski@linux.intel.com>
Assisted-by: LLM
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/nhi.c

@@ -439,6 +439,13 @@ struct ring_frame *tb_ring_poll(struct tb_ring *ring)
 		}
 
 		ring->tail = (ring->tail + 1) % ring->size;
+
+		/*
+		 * There is one more slot available so we can push next
+		 * descriptor to the ring. This is needed when the ring
+		 * is created with %RING_FLAG_NO_INTERRUPT.
+		 */
+		ring_write_descriptors(ring, true);
 	}
 
 unlock: