media: ov2680: Allow probing if link-frequencies is absent

Since commit 63b0cd30 ("media: ov2680: Add bus-cfg / endpoint
property verification") the ov2680 no longer probes on a imx7s-warp7:

ov2680 1-0036: error -EINVAL: supported link freq 330000000 not found
ov2680 1-0036: probe with driver ov2680 failed with error -22

As the 'link-frequencies' property is not mandatory, allow the probe
to succeed by skipping the link-frequency verification when the
property is absent.

Cc: stable@vger.kernel.org
Fixes: 63b0cd30 ("media: ov2680: Add bus-cfg / endpoint property verification")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/ov2680.c

@@ -1123,18 +1123,23 @@ static int ov2680_parse_dt(struct ov2680_dev *sensor)
 		goto out_free_bus_cfg;
 	}
 
+	if (!bus_cfg.nr_of_link_frequencies) {
+		dev_warn(dev, "Consider passing 'link-frequencies' in DT\n");
+		goto skip_link_freq_validation;
+	}
+
 	for (i = 0; i < bus_cfg.nr_of_link_frequencies; i++)
 		if (bus_cfg.link_frequencies[i] == sensor->link_freq[0])
 			break;
 
-	if (bus_cfg.nr_of_link_frequencies == 0 ||
-	    bus_cfg.nr_of_link_frequencies == i) {
+	if (bus_cfg.nr_of_link_frequencies == i) {
 		ret = dev_err_probe(dev, -EINVAL,
 				    "supported link freq %lld not found\n",
 				    sensor->link_freq[0]);
 		goto out_free_bus_cfg;
 	}
 
+skip_link_freq_validation:
 	ret = 0;
 out_free_bus_cfg:
 	v4l2_fwnode_endpoint_free(&bus_cfg);