AGESA: Switch to MMCONF_SUPPORT_DEFAULT

Vendorcode always does PCI MMCONF access once it is
enabled via MSR.

In coreboot proper, we don't give opportunity to make
pci_read/write calls before PCI MMCONF is enabled via MSR.
This happens early in romstage amd_initmmio() for all cores.

Change-Id: If31bc0a67b480bcc1d955632f413f5cdeec51a54
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17533
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/mainboard/amd/inagua/romstage.c b/src/mainboard/amd/inagua/romstage.c
index 3e37e03..3d0eecf 100644
--- a/src/mainboard/amd/inagua/romstage.c
+++ b/src/mainboard/amd/inagua/romstage.c
@@ -40,6 +40,7 @@
 {
 	u32 val;
 
+	/* Must come first to enable PCI MMCONF. */
 	amd_initmmio();
 
 	if (!cpu_init_detectedx && boot_cpu()) {