soc: qcom: spcom: Add mutex_unlock for device_open err case

This change adds the missing mutex_unlock for device_open of the same
client open twice error case.

Change-Id: Ib75157d0b6d04c6221727778b909f0e3d061b2c8
Signed-off-by: Li Li <liil1@codeaurora.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>

drivers/soc/qcom/spcom.c

@@ -1439,6 +1439,7 @@ static int spcom_device_open(struct inode *inode, struct file *filp)
 	 */
 	if (ch->pid == pid) {
 		pr_err("client is already registered with channel[%s]\n", name);
+		mutex_unlock(&ch->lock);
 		return -EINVAL;
 	}