northbridge/intel/fsp_rangeley: transition away from device_t

Replace the use of the old device_t definition inside
northbridge/intel/fsp_rangeley.

Change-Id: I4c1e6af64fe70211db2fafdba9f39182dfea66fc
Signed-off-by: Antonello Dettori <dev@dettori.io>
Reviewed-on: https://review.coreboot.org/16470
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/northbridge/intel/fsp_rangeley/northbridge.h

@@ -72,7 +72,7 @@ void dump_spd_registers(void);
 void dump_mem(unsigned start, unsigned end);
 void report_platform_info(void);
 
-#if ENV_RAMSTAGE
+#ifndef __SIMPLE_DEVICE__
 void northbridge_acpi_fill_ssdt_generator(device_t device);
 #endif