mb/google/octopus: Override emmc DLL values for Ampton

New emmc DLL values for Ampton

BUG=b:122307153
TEST=Boot to OS on 5 systems

Change-Id: Iadd58d254f4bb384f483c2c3e5615f7569d5211c
Signed-off-by: Kane Chen <kane.chen@intel.com>
Reviewed-on: https://review.coreboot.org/c/31048
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Justin TerAvest <teravest@chromium.org>

src/mainboard/google/octopus/variants/ampton/overridetree.cb

@@ -1,5 +1,46 @@
 chip soc/intel/apollolake
 
+	# EMMC Tx CMD Delay
+	# Refer to EDS-Vol2-16.32.
+	# [14:8] steps of delay for DDR mode, each 125ps.
+	# [6:0] steps of delay for SDR mode, each 125ps.
+	register "emmc_tx_cmd_cntl" = "0x505"
+
+	# EMMC TX DATA Delay 1
+	# Refer to EDS-Vol2-16.33.
+	# [14:8] steps of delay for HS400, each 125ps.
+	# [6:0] steps of delay for SDR104/HS200, each 125ps.
+	register "emmc_tx_data_cntl1" = "0x0a0c"
+
+	# EMMC TX DATA Delay 2
+	# Refer to EDS-Vol2-16.34.
+	# [30:24] steps of delay for SDR50, each 125ps.
+	# [22:16] steps of delay for DDR50, each 125ps.
+	# [14:8] steps of delay for SDR25/HS50, each 125ps.
+	# [6:0] steps of delay for SDR12, each 125ps.
+	register "emmc_tx_data_cntl2" = "0x1c292929"
+
+	# EMMC RX CMD/DATA Delay 1
+	# Refer to EDS-Vol2-16.35.
+	# [30:24] steps of delay for SDR50, each 125ps.
+	# [22:16] steps of delay for DDR50, each 125ps.
+	# [14:8] steps of delay for SDR25/HS50, each 125ps.
+	# [6:0] steps of delay for SDR12, each 125ps.
+	register "emmc_rx_cmd_data_cntl1" = "0x001a1c1c"
+
+	# EMMC RX CMD/DATA Delay 2
+	# Refer to EDS-Vol2-16.37.
+	# [17:16] stands for Rx Clock before Output Buffer
+	# [14:8] steps of delay for Auto Tuning Mode, each 125ps.
+	# [6:0] steps of delay for HS200, each 125ps.
+	register "emmc_rx_cmd_data_cntl2" = "0x10026"
+
+	# EMMC Rx Strobe Delay
+	# Refer to EDS-Vol2-16.36.
+	# [14:8] Rx Strobe Delay DLL 1(HS400 Mode), each 125ps.
+	# [6:0] Rx Strobe Delay DLL 2(HS400 Mode), each 125ps.
+	register "emmc_rx_strobe_cntl" = "0x0a0a"
+
 	register "common_soc_config" = "{
 		.gspi[0] = {
 			.speed_mhz = 1,