phy: usb: sunplus: Fix potential null-ptr-deref in sp_usb_phy_probe()

sp_usb_phy_probe() will call platform_get_resource_byname() that may fail
and return NULL. devm_ioremap() will use usbphy->moon4_res_mem->start as
input, which may causes null-ptr-deref. Check the ret value of
platform_get_resource_byname() to avoid the null-ptr-deref.

Fixes: 99d9ccd97385 ("phy: usb: Add USB2.0 phy driver for Sunplus SP7021")
Signed-off-by: Shang XiaoJing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

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

···
 		return PTR_ERR(usbphy->phy_regs);
 
 	usbphy->moon4_res_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "moon4");
+	if (!usbphy->moon4_res_mem)
+		return -EINVAL;
+
 	usbphy->moon4_regs = devm_ioremap(&pdev->dev, usbphy->moon4_res_mem->start,
 					  resource_size(usbphy->moon4_res_mem));
 	if (!usbphy->moon4_regs)