greybus: gpio: handle api change in generic_handle_irq_desc()

generic_handle_irq_desc changed the api in the 4.2 kernel, so fix up the
gpio driver to handle this properly to keep it working.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/gpio.c

@@ -384,7 +384,11 @@ static int gb_gpio_request_recv(u8 type, struct gb_operation *op)
 	}
 
 	local_irq_disable();
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 2, 0)
 	generic_handle_irq_desc(irq, desc);
+#else
+	generic_handle_irq_desc(desc);
+#endif
 	local_irq_enable();
 
 	return 0;