nb/intel/haswell: Consolidate memory-down SPD handling

Mainboards do not need to know about `pei_data` to tell northbridge code
where to find the SPD data. Adjust `mb_get_spd_map` to take a pointer to
a struct instead of an array, and update all the mainboards accordingly.

Currently, the only board with memory-down in the tree is google/slippy.
Mainboard code now obtains the SPD index in `mb_get_spd_map` and adjusts
the channel population accordingly. Then, northbridge code reads the SPD
file and uses the index that was read in `mb_get_spd_map`, and copies it
to channel 0 slot 0 unconditionally. MRC only uses the first position of
the `spd_data` array, and ignores the other positions. In coreboot code,
`setup_sdram_meminfo` uses the data of each SPD index, so `copy_spd` has
to account for this.

Tested on Asrock B85M Pro4, still boots and still resumes from S3.

Change-Id: Ibaed5c6de9853db6abd08f53bbfda8800d207c3e
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51448
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/northbridge/intel/haswell/raminit.h b/src/northbridge/intel/haswell/raminit.h
index 6efea3e..ff95a45 100644
--- a/src/northbridge/intel/haswell/raminit.h
+++ b/src/northbridge/intel/haswell/raminit.h
@@ -6,15 +6,19 @@
 #include <stdint.h>
 #include "pei_data.h"
 
+#define SPD_MEMORY_DOWN	0xff
+
+struct spd_info {
+	uint8_t addresses[4];
+	unsigned int spd_index;
+};
+
 /* Mainboard-specific USB configuration */
 extern const struct usb2_port_setting mainboard_usb2_ports[MAX_USB2_PORTS];
 extern const struct usb3_port_setting mainboard_usb3_ports[MAX_USB3_PORTS];
 
-/* Optional function to copy SPD data for on-board memory */
-void copy_spd(struct pei_data *peid);
-
 /* Mainboard callback to fill in the SPD addresses in MRC format */
-void mb_get_spd_map(uint8_t spd_map[4]);
+void mb_get_spd_map(struct spd_info *spdi);
 
 void sdram_initialize(struct pei_data *pei_data);
 void setup_sdram_meminfo(struct pei_data *pei_data);