PCI: artpec6: Implement dw_pcie_ep operation get_features

All non-DWC EPC drivers implement (struct pci_epc *)->ops->get_features().
All DWC EPC drivers implement (struct dw_pcie_ep *)->ops->get_features(),
except for pcie-artpec6.c.

epc_features has been required in pci-epf-test.c since commit 6613bc2
("PCI: endpoint: Fix NULL pointer dereference for ->get_features()").

A follow-up commit will make further use of epc_features in EPC core code.

Implement epc_features in the only EPC driver where it is currently not
implemented.

Link: https://lore.kernel.org/r/20241213143301.4158431-12-cassel@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

Author: floatious

drivers/pci/controller/dwc/pcie-artpec6.c

@@ -369,9 +369,22 @@ static int artpec6_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
 	return 0;
 }
 
+static const struct pci_epc_features artpec6_pcie_epc_features = {
+	.linkup_notifier = false,
+	.msi_capable = true,
+	.msix_capable = false,
+};
+
+static const struct pci_epc_features *
+artpec6_pcie_get_features(struct dw_pcie_ep *ep)
+{
+	return &artpec6_pcie_epc_features;
+}
+
 static const struct dw_pcie_ep_ops pcie_ep_ops = {
 	.init = artpec6_pcie_ep_init,
 	.raise_irq = artpec6_pcie_raise_irq,
+	.get_features = artpec6_pcie_get_features,
 };
 
 static int artpec6_pcie_probe(struct platform_device *pdev)