platform/mellanox: mlxbf-pmc: Fix an IS_ERR() vs NULL bug in mlxbf_pmc_map_counters

The devm_ioremap() function returns NULL on error, it doesn't return
error pointers. Also according to doc of device_property_read_u64_array,
values in info array are properties of device or NULL.
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Link: https://lore.kernel.org/r/20211210070753.10761-1-linmq006@gmail.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/mellanox/mlxbf-pmc.c

@@ -1374,8 +1374,8 @@ static int mlxbf_pmc_map_counters(struct device *dev)
 		pmc->block[i].counters = info[2];
 		pmc->block[i].type = info[3];
 
-		if (IS_ERR(pmc->block[i].mmio_base))
-			return PTR_ERR(pmc->block[i].mmio_base);
+		if (!pmc->block[i].mmio_base)
+			return -ENOMEM;
 
 		ret = mlxbf_pmc_create_groups(dev, i);
 		if (ret)