superio/nsc/pc87417: Use link-time symbols over .c inclusion

Change-Id: I2efb7ab4b69bcd127b2faf54277dc229c9dcf3ea
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/8078
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)
diff --git a/src/mainboard/msi/ms9185/romstage.c b/src/mainboard/msi/ms9185/romstage.c
index aabc826..bd82436 100644
--- a/src/mainboard/msi/ms9185/romstage.c
+++ b/src/mainboard/msi/ms9185/romstage.c
@@ -40,7 +40,7 @@
 #include "cpu/x86/lapic.h"
 #include "northbridge/amd/amdk8/reset_test.c"
 #include "northbridge/amd/amdk8/debug.c"
-#include "superio/nsc/pc87417/early_serial.c"
+#include <superio/nsc/pc87417/pc87417.h>
 #include "cpu/x86/bist.h"
 #include "northbridge/amd/amdk8/setup_resource_map.c"
 #include "southbridge/broadcom/bcm5785/early_setup.c"