usb: isp1760: Use kasprintf

Use kasprintf instead of combination of kmalloc and sprintf and
therefore avoid unnecessary computation of string length.
Also, remove the useless local variable.

Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/isp1760/isp1760-udc.c

@@ -1441,7 +1441,6 @@ int isp1760_udc_register(struct isp1760_device *isp, int irq,
 			 unsigned long irqflags)
 {
 	struct isp1760_udc *udc = &isp->udc;
-	const char *devname;
 	int ret;
 
 	udc->irq = -1;
@@ -1455,13 +1454,10 @@ int isp1760_udc_register(struct isp1760_device *isp, int irq,
 	if (ret < 0)
 		return ret;
 
-	devname = dev_name(isp->dev);
-	udc->irqname = kmalloc(strlen(devname) + 7, GFP_KERNEL);
+	udc->irqname = kasprintf(GFP_KERNEL, "%s (udc)", dev_name(isp->dev));
 	if (!udc->irqname)
 		return -ENOMEM;
 
-	sprintf(udc->irqname, "%s (udc)", devname);
-
 	ret = request_irq(irq, isp1760_udc_irq, IRQF_SHARED | irqflags,
 			  udc->irqname, udc);
 	if (ret < 0)