tty: serial: msm_geni_serial: Fix return value check in qcom_geni_serial_probe()

In case of error, the function platform_get_resource() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Fixes: c4f52879 ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/qcom_geni_serial.c

@@ -1053,8 +1053,8 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (IS_ERR(res))
-		return PTR_ERR(res);
+	if (!res)
+		return -EINVAL;
 	uport->mapbase = res->start;
 
 	port->tx_fifo_depth = DEF_FIFO_DEPTH_WORDS;