usb: gadget: udc: s3c2410: add IRQ check

The driver neglects to check the result of platform_get_irq()'s call and
blithely passes the negative error codes to request_irq() (which takes
*unsigned* IRQ #), causing it to fail with -EINVAL, overriding an original
error code. Stop calling request_irq() with the invalid IRQ #s.

Fixes: 188db4435ac6 ("usb: gadget: s3c: use platform resources")
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Felipe Balbi <[e-mail]>
Signed-off-by: Sergey Shtylyov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/gadget/udc/s3c2410_udc.c

···
 	s3c2410_udc_reinit(udc);
 
 	irq_usbd = platform_get_irq(pdev, 0);
+	if (irq_usbd < 0) {
+		retval = irq_usbd;
+		goto err_udc_clk;
+	}
 
 	/* irq setup after old hardware state is cleaned up */
 	retval = request_irq(irq_usbd, s3c2410_udc_irq,