mb/google/rex: Override LP5 CCC config

This patch overrides `Lp5CccConfig` UPD as per the CCC mapping data
captured from the Rex schematics dated 07/16.

BUG=b:224325352
TEST=Able to build Google/Rex.

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: Ia1d9e3665cff74a803e730c76f62773996efb3dd
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66049
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/rex/variants/baseboard/rex/memory.c

@@ -6,7 +6,9 @@
 
 static const struct mb_cfg baseboard_memcfg = {
 	.type = MEM_TYPE_LP5X,
-	/* TODO: Add Memory configuration */
+	.lp5x_config = {
+		.ccc_config = 0x66,
+	},
 	.ect = 1, /* Enable Early Command Training */
 };