southbridge/intel/ibexpeak: Use common gpio.c

Use shared gpio code from common folder.
Remove the now unused bd82x6x/gpio.c.

Needs test on real hardware !

Change-Id: Ibb54c03fd83a529d1ceccfb2c33190e7d42224d8
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/13616
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/southbridge/intel/ibexpeak/smihandler.c

@@ -32,6 +32,7 @@
  *  2. we don't need to worry about how we leave 0xcf8/0xcfc behind
  */
 #include "northbridge/intel/nehalem/nehalem.h"
+#include <southbridge/intel/common/gpio.h>
 #include <arch/pci_mmio_cfg.h>
 
 /* While we read PMBASE dynamically in case it changed, let's