qtnfmac: modify qtnf_map_bar not to return NULL

NULL is not a special type of success here but a error pointer.
So it makes sense to check against NULL in qtnf_map_bar
and return error code.
Signed-off-by: NSergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/quantenna/qtnfmac/pearl/pcie.c

@@ -184,8 +184,10 @@ static void __iomem *qtnf_map_bar(struct qtnf_pcie_bus_priv *priv, u8 index)
 		return IOMEM_ERR_PTR(ret);
 
 	busaddr = pci_resource_start(priv->pdev, index);
-	vaddr = pcim_iomap_table(priv->pdev)[index];
 	len = pci_resource_len(priv->pdev, index);
+	vaddr = pcim_iomap_table(priv->pdev)[index];
+	if (!vaddr)
+		return IOMEM_ERR_PTR(-ENOMEM);
 
 	pr_debug("BAR%u vaddr=0x%p busaddr=%pad len=%u\n",
 		 index, vaddr, &busaddr, (int)len);
@@ -248,19 +250,19 @@ static int qtnf_pcie_init_memory(struct qtnf_pcie_bus_priv *priv)
 	int ret = -ENOMEM;
 
 	priv->sysctl_bar = qtnf_map_bar(priv, QTN_SYSCTL_BAR);
-	if (IS_ERR_OR_NULL(priv->sysctl_bar)) {
+	if (IS_ERR(priv->sysctl_bar)) {
 		pr_err("failed to map BAR%u\n", QTN_SYSCTL_BAR);
 		return ret;
 	}
 
 	priv->dmareg_bar = qtnf_map_bar(priv, QTN_DMA_BAR);
-	if (IS_ERR_OR_NULL(priv->dmareg_bar)) {
+	if (IS_ERR(priv->dmareg_bar)) {
 		pr_err("failed to map BAR%u\n", QTN_DMA_BAR);
 		return ret;
 	}
 
 	priv->epmem_bar = qtnf_map_bar(priv, QTN_SHMEM_BAR);
-	if (IS_ERR_OR_NULL(priv->epmem_bar)) {
+	if (IS_ERR(priv->epmem_bar)) {
 		pr_err("failed to map BAR%u\n", QTN_SHMEM_BAR);
 		return ret;
 	}