misc/pvpanic: fix return value check in pvpanic_pci_probe()

In case of error, the function pci_iomap() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qiheng Lin <linqiheng@huawei.com>
Link: https://lore.kernel.org/r/20210330013659.916-1-linqiheng@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/pvpanic/pvpanic-pci.c

@@ -83,8 +83,8 @@ static int pvpanic_pci_probe(struct pci_dev *pdev,
 		return ret;
 
 	base = pci_iomap(pdev, 0, 0);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	if (!base)
+		return -ENOMEM;
 
 	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
 	if (!pi)