iommu/mediatek: Cleanup pericfg lookup flow

Since only the INFRA type IOMMU needs to modify register(s) in the
pericfg iospace, it's safe to drop the pericfg_comp_str NULL check;
also, directly assign the regmap handle to data->pericfg instead of
to the infracfg variable to improve code readability.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20220616110830.26037-6-angelogioacchino.delregno@collabora.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: AngeloGioacchino Del Regno

drivers/iommu/mtk_iommu.c

@@ -1217,15 +1217,13 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 			dev_err(dev, "mm dts parse fail(%d).", ret);
 			goto out_runtime_disable;
 		}
-	} else if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_INFRA) &&
-		   data->plat_data->pericfg_comp_str) {
-		infracfg = syscon_regmap_lookup_by_compatible(data->plat_data->pericfg_comp_str);
-		if (IS_ERR(infracfg)) {
-			ret = PTR_ERR(infracfg);
+	} else if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_INFRA)) {
+		p = data->plat_data->pericfg_comp_str;
+		data->pericfg = syscon_regmap_lookup_by_compatible(p);
+		if (IS_ERR(data->pericfg)) {
+			ret = PTR_ERR(data->pericfg);
 			goto out_runtime_disable;
 		}
-
-		data->pericfg = infracfg;
 	}
 
 	platform_set_drvdata(pdev, data);