platform/mellanox: mlxbf-pmc: fix sscanf() error checking

The sscanf() function never returns negatives.  It returns the number of
items successfully read.

Fixes: 1a218d3 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/4ccdfd28-099b-40bf-8d77-ad4ea2e76b93@kili.mountain
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Author: Dan Carpenter

drivers/platform/mellanox/mlxbf-pmc.c

@@ -1348,9 +1348,8 @@ static int mlxbf_pmc_map_counters(struct device *dev)
 
 	for (i = 0; i < pmc->total_blocks; ++i) {
 		if (strstr(pmc->block_name[i], "tile")) {
-			ret = sscanf(pmc->block_name[i], "tile%d", &tile_num);
-			if (ret < 0)
-				return ret;
+			if (sscanf(pmc->block_name[i], "tile%d", &tile_num) != 1)
+				return -EINVAL;
 
 			if (tile_num >= pmc->tile_count)
 				continue;