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/Kconfig

@@ -33,6 +33,7 @@ config SOUTH_BRIDGE_OPTIONS # dummy
 	select COMMON_FADT
 	select ACPI_SATA_GENERATOR
 	select HAVE_INTEL_FIRMWARE
+	select SOUTHBRIDGE_INTEL_COMMON_GPIO
 
 config EHCI_BAR
 	hex