mb/google/brya/var/xol: Enable FSP UPD LpDdrDqDqsReTraining

Set LpDdrDqDqsReTraining to 1 for xol. Value 0 will cause black screen
issue.

Reference: https://review.coreboot.org/c/coreboot/+/79527
> FSP default value for LpDdrDqDqsReTraining is 1. For boards
> that didn't set LpDdrDqDqsReTraining to any value, 0 was being
> assigned and it caused black screen issue.

BUG=b:332980211
BRANCH=brya
TEST=Built and verified there is no black screen issue during power
on/off test for over 100 cycles.

Change-Id: Ia346ce559b4509ea1a63abe28b12ad909f9b7b0d
Signed-off-by: Seunghwan Kim <sh_.kim@samsung.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82778
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>

src/mainboard/google/brya/variants/xol/memory.c

@@ -63,6 +63,8 @@ static const struct mb_cfg variant_memcfg = {
 		.ccc_config = 0xff,
 	},
 
+	.LpDdrDqDqsReTraining = 1,
+
 	.ect = 1, /* Early Command Training */
 
 	.UserBd = BOARD_TYPE_ULT_ULX,