HID: hid-uclogic-params: Invalid parameter check in uclogic_params_get_str_desc

The function performs a check on the hdev input parameters, however, it
is used before the check.

Initialize the udev variable after the sanity check to avoid a
possible NULL pointer dereference.

Fixes: 9614219e ("HID: uclogic: Extract tablet parameter discovery into a module")
Addresses-Coverity-ID: 1443827 ("Null pointer dereference")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-uclogic-params.c

@@ -66,7 +66,7 @@ static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
 					__u8 idx, size_t len)
 {
 	int rc;
-	struct usb_device *udev = hid_to_usb_dev(hdev);
+	struct usb_device *udev;
 	__u8 *buf = NULL;
 
 	/* Check arguments */
@@ -75,6 +75,8 @@ static int uclogic_params_get_str_desc(__u8 **pbuf, struct hid_device *hdev,
 		goto cleanup;
 	}
 
+	udev = hid_to_usb_dev(hdev);
+
 	buf = kmalloc(len, GFP_KERNEL);
 	if (buf == NULL) {
 		rc = -ENOMEM;