memory: renesas-rpc-if: Return error in case devm_ioremap_resource() fails

Make sure we return error in case devm_ioremap_resource() fails for dirmap
resource.

Fixes: ca7d8b98 ("memory: add Renesas RPC-IF driver")
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211025205631.21151-6-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

drivers/memory/renesas-rpc-if.c

@@ -243,7 +243,7 @@ int rpcif_sw_init(struct rpcif *rpc, struct device *dev)
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dirmap");
 	rpc->dirmap = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(rpc->dirmap))
-		rpc->dirmap = NULL;
+		return PTR_ERR(rpc->dirmap);
 	rpc->size = resource_size(res);
 
 	rpc->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);