usb: fotg210: fix return value check in fotg210_probe()

devm_platform_get_and_ioremap_resource() never returns NULL pointer,
it will return ERR_PTR() when it fails, so replace the check with
IS_ERR().

Fixes: baef5330d35b ("usb: fotg210: Acquire memory resource in core")
Signed-off-by: Yang Yingliang <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/fotg210/fotg210-core.c

···
 	fotg->dev = dev;
 
 	fotg->base = devm_platform_get_and_ioremap_resource(pdev, 0, &fotg->res);
-	if (!fotg->base)
-		return -ENOMEM;
+	if (IS_ERR(fotg->base))
+		return PTR_ERR(fotg->base);
 
 	fotg->pclk = devm_clk_get_optional_enabled(dev, "PCLK");
 	if (IS_ERR(fotg->pclk))