southbridge/intel/ibexpeak: transition away from device_t

Replace the use of the old device_t definition inside
southbridge/intel/ibexpeak.

The patch has been tested both with the arch/io.h definition of device_t
enabled and disabled in order to ensure compatibility while the
transaction takes place.

Change-Id: Ic569aada9301b37e73196872584e191d553acd86
Signed-off-by: Antonello Dettori <dev@dettori.io>
Reviewed-on: https://review.coreboot.org/16408
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/southbridge/intel/ibexpeak/pch.h

@@ -61,7 +61,7 @@ void intel_pch_finalize_smm(void);
 
 #if !defined(__ASSEMBLER__)
 #if !defined(__PRE_RAM__)
-#if !defined(__SMM__)
+#if !defined(__SIMPLE_DEVICE__)
 #include "chip.h"
 void pch_enable(device_t dev);
 #endif