intel PCI ops: Remove explicit PCI MMCONF access

MMCONF was explicitly used here to avoid races of 0xcf8/0xcfc access
being non-atomic and/or need to access 4kiB of PCI config space.

All these platforms now have MMCONF_SUPPORT_DEFAULT.

Change-Id: If62537475eb67b7ecf85f2292a2a954a41bc18d1
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/17545
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/southbridge/intel/ibexpeak/smihandler.c

@@ -33,7 +33,7 @@
  */
 #include "northbridge/intel/nehalem/nehalem.h"
 #include <southbridge/intel/common/gpio.h>
-#include <arch/pci_mmio_cfg.h>
+#include <arch/io.h>
 
 /* While we read PMBASE dynamically in case it changed, let's
  * initialize it with a sane value