usb: gadget: dummy_hcd: fix error return code in init()

Fix to return -ENOMEM in the kzalloc() error handling case instead
of 0(following platform_device_add_data() will overwrite it to 0), as
done elsewhere in this function.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/gadget/dummy_hcd.c

@@ -2660,8 +2660,10 @@ static int __init init(void)
 	}
 	for (i = 0; i < mod_data.num; i++) {
 		dum[i] = kzalloc(sizeof(struct dummy), GFP_KERNEL);
-		if (!dum[i])
+		if (!dum[i]) {
+			retval = -ENOMEM;
 			goto err_add_pdata;
+		}
 		retval = platform_device_add_data(the_hcd_pdev[i], &dum[i],
 				sizeof(void *));
 		if (retval)