Unlock mhdp->link_mutex before returning.

This bug has been detected by the Clang thread-safety analyzer.

Cc: Aleksandr Mishin <amishin@t-argos.ru>
Cc: Robert Foss <rfoss@kernel.org>
Fixes: 935a92a1c400 ("drm: bridge: cdns-mhdp8546: Fix possible null pointer dereference")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 9295b2a9f9be..51e2caa9c815 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2053,8 +2053,10 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge *bridge,
 	mhdp_state = to_cdns_mhdp_bridge_state(new_state);
 
 	mhdp_state->current_mode = drm_mode_duplicate(bridge->dev, mode);
-	if (!mhdp_state->current_mode)
-		return;
+	if (!mhdp_state->current_mode) {
+		ret = 0;
+		goto out;
+	}
 
 	drm_mode_set_name(mhdp_state->current_mode);