haswell: Make `copy_spd` a weak function

Instead of using function pointers, we can use weak functions. So, drop
the pointer from `romstage_params`, leaving `pei_data` as the only
remaining member. This will be cleaned up in a follow-up commit.

Change-Id: I3b17d21ea7a650734119a5cab4892fcb158b589d
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43105
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/northbridge/intel/haswell/romstage.c b/src/northbridge/intel/haswell/romstage.c
index ae9d707..00f5f47 100644
--- a/src/northbridge/intel/haswell/romstage.c
+++ b/src/northbridge/intel/haswell/romstage.c
@@ -13,6 +13,11 @@
 #include <southbridge/intel/lynxpoint/pch.h>
 #include <southbridge/intel/lynxpoint/me.h>
 
+/* Copy SPD data for on-board memory */
+void __weak copy_spd(struct pei_data *peid)
+{
+}
+
 void __weak mb_late_romstage_setup(void)
 {
 }
@@ -53,8 +58,7 @@
 
 	report_platform_info();
 
-	if (params->copy_spd != NULL)
-		params->copy_spd(params->pei_data);
+	copy_spd(params->pei_data);
 
 	sdram_initialize(params->pei_data);