util/autoport: Use romstage.c instead of early_southbridge.c

Until now, autoport used to create a dummy "romstage.c", then write
romstage code to "early_southbridge.c". While it works, it makes more
sense to write to "romstage.c" instead, as virtually all mainboards do.

Change-Id: If9f9375f9a659e7e685de5f884163813261fa656
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/28851
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/autoport/bd82x6x.go

@@ -299,9 +299,8 @@ func (b bd82x6x) Scan(ctx Context, addr PCIDevData) {
 		File: "southbridge/intel/bd82x6x/acpi/pch.asl",
 	})
 
-	sb := Create(ctx, "early_southbridge.c")
+	sb := Create(ctx, "romstage.c")
 	defer sb.Close()
-	AddROMStageFile("early_southbridge.c", "")
 	Add_gpl(sb)
 	sb.WriteString(`#include <stdint.h>
 #include <string.h>

util/autoport/main.go

@@ -827,10 +827,6 @@ func main() {
 		fmt.Fprintf(bi, "FIXME: put %s\n", missing)
 	}
 
-	rs := Create(ctx, "romstage.c")
-	defer rs.Close()
-	rs.WriteString("/* dummy file */\n")
-
 	if ROMSizeKB == 0 {
 		KconfigBool["BOARD_ROMSIZE_KB_2048"] = true
 		KconfigComment["BOARD_ROMSIZE_KB_2048"] = "FIXME: correct this"