haswell: relocate `romstage_common` to northbridge

Other platforms do this as well. It will ease refactoring on follow-ups.

Change-Id: I643982a58c6f5370c78acef93740f27df001a06d
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43093
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tristan Corrick <tristan@corrick.kiwi>
diff --git a/src/northbridge/intel/haswell/haswell.h b/src/northbridge/intel/haswell/haswell.h
index c393049..b98d880 100644
--- a/src/northbridge/intel/haswell/haswell.h
+++ b/src/northbridge/intel/haswell/haswell.h
@@ -189,6 +189,16 @@
 
 void intel_northbridge_haswell_finalize_smm(void);
 
+struct pei_data;
+struct rcba_config_instruction;
+struct romstage_params {
+	struct pei_data *pei_data;
+	const void *gpio_map;
+	const struct rcba_config_instruction *rcba_config;
+	void (*copy_spd)(struct pei_data *peid);
+};
+void romstage_common(const struct romstage_params *params);
+
 void haswell_early_initialization(void);
 void haswell_late_initialization(void);
 void set_translation_table(int start, int end, u64 base, int inc);