i2c: cadence: add IRQ check

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

Fixes: df8eb5691c ("i2c: Add driver for Cadence I2C controller")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-cadence.c

@@ -1200,7 +1200,10 @@ static int cdns_i2c_probe(struct platform_device *pdev)
 	if (IS_ERR(id->membase))
 		return PTR_ERR(id->membase);
 
-	id->irq = platform_get_irq(pdev, 0);
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+	id->irq = ret;
 
 	id->adap.owner = THIS_MODULE;
 	id->adap.dev.of_node = pdev->dev.of_node;