usb: cdns3: Don't use priv_dev uninitialized in cdns3_gadget_ep_enable()

Clang warns:

drivers/usb/cdns3/cdns3-gadget.c:2290:11: error: variable 'priv_dev' is uninitialized when used here [-Werror,-Wuninitialized]
dev_dbg(priv_dev->dev, "usbss: invalid parameters\n");
^~~~~~~~
include/linux/dev_printk.h:155:18: note: expanded from macro 'dev_dbg'
dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__)
^~~
include/linux/dynamic_debug.h:167:7: note: expanded from macro 'dynamic_dev_dbg'
dev, fmt, ##__VA_ARGS__)
^~~
include/linux/dynamic_debug.h:152:56: note: expanded from macro '_dynamic_func_call'
__dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
^~~~~~~~~~~
include/linux/dynamic_debug.h:134:15: note: expanded from macro '__dynamic_func_call'
func(&id, ##__VA_ARGS__); \
^~~~~~~~~~~
drivers/usb/cdns3/cdns3-gadget.c:2278:31: note: initialize the variable 'priv_dev' to silence this warning
struct cdns3_device *priv_dev;
^
= NULL
1 error generated.

The priv_dev assignment was moved below the if statement to avoid
potentially dereferencing ep before it was checked but priv_dev is used
in the dev_dbg() call.

To fix this, move the priv_dev and comp_desc assignments back to their
original spot and hoist the ep check above those assignments with a call
to pr_debug() instead of dev_dbg().

Fixes: c3ffc9c4ca44 ("usb: cdns3: change place of 'priv_ep' assignment in cdns3_gadget_ep_dequeue(), cdns3_gadget_ep_enable()")
Link: https://github.com/ClangBuiltLinux/linux/issues/1680
Signed-off-by: Nathan Chancellor <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/usb/cdns3/cdns3-gadget.c

···
 	int ret = 0;
 	int val;
 
-	priv_ep = ep_to_cdns3_ep(ep);
-
-	if (!ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
-		dev_dbg(priv_dev->dev, "usbss: invalid parameters\n");
+	if (!ep) {
+		pr_debug("usbss: ep not configured?\n");
 		return -EINVAL;
 	}
 
-	comp_desc = priv_ep->endpoint.comp_desc;
+	priv_ep = ep_to_cdns3_ep(ep);
 	priv_dev = priv_ep->cdns3_dev;
+	comp_desc = priv_ep->endpoint.comp_desc;
+
+	if (!desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
+		dev_dbg(priv_dev->dev, "usbss: invalid parameters\n");
+		return -EINVAL;
+	}
 
 	if (!desc->wMaxPacketSize) {
 		dev_err(priv_dev->dev, "usbss: missing wMaxPacketSize\n");