phy: sunplus: Fix an IS_ERR() vs NULL bug in sp_usb_phy_probe

The devm_ioremap() function returns NULL on error, it doesn't return
error pointers.

Fixes: 99d9ccd9 ("phy: usb: Add USB2.0 phy driver for Sunplus SP7021")
Signed-off-by: Peng Wu <wupeng58@huawei.com>
Link: https://lore.kernel.org/r/20220911060053.123594-1-wupeng58@huawei.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/sunplus/phy-sunplus-usb2.c

@@ -256,8 +256,8 @@ static int sp_usb_phy_probe(struct platform_device *pdev)
 	usbphy->moon4_res_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "moon4");
 	usbphy->moon4_regs = devm_ioremap(&pdev->dev, usbphy->moon4_res_mem->start,
 					  resource_size(usbphy->moon4_res_mem));
-	if (IS_ERR(usbphy->moon4_regs))
-		return PTR_ERR(usbphy->moon4_regs);
+	if (!usbphy->moon4_regs)
+		return -ENOMEM;
 
 	usbphy->phy_clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(usbphy->phy_clk))