PCI: dwc: Restore ATU memory resource setup to use last entry

Prior to commit 0f71c60f ("PCI: dwc: Remove storing of PCI resources"),
the DWC driver was setting up the last memory resource rather than the
first memory resource. This doesn't matter for most platforms which only
have 1 memory resource, but it broke Tegra194 which has a 2nd
(prefetchable) memory region that requires an ATU entry. The first region
on Tegra194 relies on the default 1:1 pass-thru of outbound transactions
and doesn't need an ATU entry.

Fixes: 0f71c60f ("PCI: dwc: Remove storing of PCI resources")
Link: https://lore.kernel.org/r/20201026154852.221483-1-robh@kernel.orgReported-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -586,8 +586,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 	 * ATU, so we should not program the ATU here.
 	 */
 	if (pp->bridge->child_ops == &dw_child_pcie_ops) {
-		struct resource_entry *entry =
-			resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM);
+		struct resource_entry *tmp, *entry = NULL;
+
+		/* Get last memory resource entry */
+		resource_list_for_each_entry(tmp, &pp->bridge->windows)
+			if (resource_type(tmp->res) == IORESOURCE_MEM)
+				entry = tmp;
 
 		dw_pcie_prog_outbound_atu(pci, PCIE_ATU_REGION_INDEX0,
 					  PCIE_ATU_TYPE_MEM, entry->res->start,