[PATCH v2] soundwire: stream: fix bad unlock balance

[Srinivas Kandagatla]

multi bank switching code takes lock on condition but releases without
any check resulting in below warning.
This patch fixes this.

 =====================================
 WARNING: bad unlock balance detected!
 5.1.0-16506-gc1c383a6f0a2-dirty #1523 Tainted: G        W
 -------------------------------------
 aplay/2954 is trying to release lock (&bus->msg_lock) at:
 do_bank_switch+0x21c/0x480
 but there are no more locks to release!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
 drivers/soundwire/stream.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index ce9cb7fa4724..73c52cd4fec8 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -814,7 +814,8 @@ static int do_bank_switch(struct sdw_stream_runtime *stream)
 			goto error;
 		}
 
-		mutex_unlock(&bus->msg_lock);
+		if (bus->multi_link)
+			mutex_unlock(&bus->msg_lock);
 	}
 
 	return ret;
-- 
2.21.0