dram/ddr3: Use the same naming convention as DDR4

Change-Id: Ifaff19c0117b5247d3321605ccc2e97bf8226ca8
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82216
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/device/dram/ddr3.c b/src/device/dram/ddr3.c
index 8d2752b..09a4e7f 100644
--- a/src/device/dram/ddr3.c
+++ b/src/device/dram/ddr3.c
@@ -365,7 +365,7 @@
 	memcpy(dimm->part_number, &spd[128], 16);
 	printram("  Part number        : %s\n", dimm->part_number);
 
-	memcpy(dimm->serial, &spd[SPD_DIMM_SERIAL_NUM], SPD_DIMM_SERIAL_LEN);
+	memcpy(dimm->serial, &spd[SPD_DDR3_SERIAL_NUM], SPD_DDR3_SERIAL_LEN);
 
 	return ret;
 }