[PATCH -next] ptp: Fix missing unlock on error in idtcm_probe()

[Wei Yongjun <weiyongjun1@xxxxxxxxxx>]

Add the missing unlock before return from function idtcm_probe()
in the error handling case.

Fixes: 3a6ba7dc7799 ("ptp: Add a ptp clock driver for IDT ClockMatrix.")
Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
---
 drivers/ptp/ptp_clockmatrix.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index cf5889b7d825..a5110b7b4ece 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -1294,8 +1294,10 @@ static int idtcm_probe(struct i2c_client *client,
 
 	err = set_tod_write_overhead(idtcm);
 
-	if (err)
+	if (err) {
+		mutex_unlock(&idtcm->reg_lock);
 		return err;
+	}
 
 	err = idtcm_load_firmware(idtcm, &client->dev);