mb/google/peppy: Add Hynix memory HMT425S6CFR6A support

Adapted from Chromium commit b8dcb1a [Peppy: Update Memory IDs]

Add Hynix memory HMT425S6CFR6A support.
RAM_ID: 011 4GB Hynix HMT425S6CFR6A
RAM_ID: 111 2GB Hynix HMT425S6CFR6A

Original-Change-Id: I26d5c4ad00509e7823c325ee8391e0b18fee44d8
Original-Signed-off-by: David Wu <David_Wu@quantatw.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/1074849
Original-Reviewed-by: Duncan Laurie <dlaurie@google.com>
Original-Tested-by: David Wu <david_wu@quanta.corp-partner.google.com>

Change-Id: I4d165f61b8a13e5ed025e9ddbc4330db88e2fa3d
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37941
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/mainboard/google/slippy/variants/peppy/romstage.c b/src/mainboard/google/slippy/variants/peppy/romstage.c
index a6815c8..8adf4b2 100644
--- a/src/mainboard/google/slippy/variants/peppy/romstage.c
+++ b/src/mainboard/google/slippy/variants/peppy/romstage.c
@@ -107,8 +107,8 @@
 
 	case PEPPY_BOARD_VERSION_EVT:
 	default:
-		/* Index 0-2 are 4GB config with both CH0 and CH1.
-		 * Index 4-6 are 2GB config with CH0 only. */
+		/* Index 0-3 are 4GB config with both CH0 and CH1.
+		 * Index 4-7 are 2GB config with CH0 only. */
 		if (spd_index > 3)
 			peid->dimm_channel1_disabled = 3;
 		else