PCI: mvebu: Fix support for PCI_EXP_DEVCTL on emulated bridge

Comment in Armada 370 functional specification is misleading.
PCI_EXP_DEVCTL_*RE bits are supported and configures receiving of error
interrupts.

Link: https://lore.kernel.org/r/20211125124605.25915-14-pali@kernel.org
Fixes: 1f08673 ("PCI: mvebu: Convert to PCI emulated bridge config space")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

Author: pali

drivers/pci/controller/pci-mvebu.c

@@ -534,9 +534,7 @@ mvebu_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
 		break;
 
 	case PCI_EXP_DEVCTL:
-		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL) &
-				 ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
-				   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
+		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
 		break;
 
 	case PCI_EXP_LNKCAP:
@@ -647,13 +645,6 @@ mvebu_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
 
 	switch (reg) {
 	case PCI_EXP_DEVCTL:
-		/*
-		 * Armada370 data says these bits must always
-		 * be zero when in root complex mode.
-		 */
-		new &= ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
-			 PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
-
 		mvebu_writel(port, new, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
 		break;