mb/siemens/mc_apl{1,2,3,5,6}: Set PCI bus master bit only if allowed

Take Kconfig switch PCI_ALLOW_BUS_MASTER into account and set the PCI
bus master bit for legacy devices only if it is allowed.

Change-Id: I7798a767d528419bb093f301140ab68cc8b9c5ae
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56442
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
diff --git a/src/mainboard/siemens/mc_apl1/mainboard.c b/src/mainboard/siemens/mc_apl1/mainboard.c
index bca0cbb..114d6e3 100644
--- a/src/mainboard/siemens/mc_apl1/mainboard.c
+++ b/src/mainboard/siemens/mc_apl1/mainboard.c
@@ -215,10 +215,12 @@
 	/* Do board specific things */
 	variant_mainboard_final();
 
-	/* Set Master Enable for on-board PCI device. */
-	dev = dev_find_device(PCI_VENDOR_ID_SIEMENS, 0x403f, 0);
-	if (dev) {
-		pci_or_config16(dev, PCI_COMMAND, PCI_COMMAND_MASTER);
+	/* Set Master Enable for on-board PCI device if allowed. */
+	if (CONFIG(PCI_ALLOW_BUS_MASTER)) {
+		dev = dev_find_device(PCI_VENDOR_ID_SIEMENS, 0x403f, 0);
+		if (dev) {
+			pci_or_config16(dev, PCI_COMMAND, PCI_COMMAND_MASTER);
+		}
 	}
 	/* Set up SPI OPCODE menu before the controller is locked. */
 	fast_spi_set_opcode_menu();