soc/intel/tigerlake: Check SPD is not NULL before print

Check SPD is not NULL before print. This can prevent the system
from hanging up.

BUG=b:154445630
TEST=Check NULL SPD is not print.

Signed-off-by: Eric Lai <ericr_lai@compal.corp-partner.google.com>
Change-Id: Iccd9fce99eda7ae2b8fb1b4f3c2e635c2a428f04
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40560
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/tigerlake/meminit.c

@@ -315,8 +315,13 @@ static void read_sodimm_spd(const struct spd_info *info, struct spd_block *blk)
 
 	get_spd_smbus(blk);
 
+	/*
+	 * SPD gets printed only if:
+	 * a) mainboard provides a non-zero SMBus address and
+	 * b) SPD is successfully read using the SMBus address
+	 */
 	for (i = 0; i < ARRAY_SIZE(blk->addr_map); i++) {
-		if (blk->addr_map[i])
+		if (blk->spd_array[i] != NULL)
 			print_spd_info((uint8_t *)blk->spd_array[i]);
 	}
 }