drm/rockchip: vop2: unlock on error path in vop2_crtc_atomic_enable()

This error path needs an unlock before returning.

Fixes: 604be855 ("drm/rockchip: Add VOP2 driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YnjZQRV9lpub2ET8@kili

drivers/gpu/drm/rockchip/rockchip_drm_vop2.c

@@ -1524,6 +1524,7 @@ static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
 	if (ret < 0) {
 		drm_err(vop2->drm, "failed to enable dclk for video port%d - %d\n",
 			vp->id, ret);
+		vop2_unlock(vop2);
 		return;
 	}