mb/google/kukui: Add LPDDR4X MT53E2G32D4NQ-046 8GB support for burnet/esche

Add LPDDR4x DRAM index#6 MT53E2G32D4NQ-046 8GB

BUG=b:159301679
BRANCH=master
TEST=1. emerge-jacuzzi coreboot
     2. MT53E2G32D4NQ-046 8GB M/B boot successfully
     3. check DRAM size: 8GB

Change-Id: I16449591ec576b1c613a5dad511bafac2bb46f04
Signed-off-by: Kevin Chiu <kevin.chiu@quantatw.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44520
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

src/mainboard/google/kukui/sdram_configs.c

@@ -28,6 +28,7 @@ static const char *const sdram_configs[] = {
 	[0x12] = "sdram-lpddr4x-MT53E1G32D4NQ-4GB",
 	[0x13] = "sdram-lpddr4x-K4UBE3D4AA-MGCL-4GB",
 	[0x14] = "sdram-lpddr4x-H9HCNNNCPMMLXR-NEE-4GB",
+	[0x16] = "sdram-lpddr4x-MT53E2G32D4NQ-046-8GB",
 };
 
 static struct sdram_params params;