mb/google/octopus: adjust Bobba I2C CLK under 400KHz

Need to tune I2C bus 0/6/7 clock frequency under the 400KHz for
digitizer, touchpad, and touchscreen.

Bug=b:117126484
TEST=flash coreboot to the DUT and measure I2C bus 0/6/7 clock
frequency whether can <400KHz

Change-Id: Icb9592c688b864a21efd4963a4463845dfaa06fb
Signed-off-by: Pan Sheng-Liang <sheng-liang.pan@quanta.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/28907
Reviewed-by: Justin TerAvest <teravest@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

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

@@ -1,5 +1,46 @@
 chip soc/intel/apollolake
 
+	# Intel Common SoC Config
+	#+-------------------+---------------------------+
+	#| Field             |  Value                    |
+	#+-------------------+---------------------------+
+	#| GSPI0             | cr50 TPM. Early init is   |
+	#|                   | required to set up a BAR  |
+	#|                   | for TPM communication     |
+	#|                   | before memory is up       |
+	#| I2C0              | Digitizer                 |
+	#| I2C5              | Audio                     |
+	#| I2C6              | Trackpad                  |
+	#| I2C7              | Touchscreen               |
+	#+-------------------+---------------------------+
+	register "common_soc_config" = "{
+		.gspi[0] = {
+			.speed_mhz = 1,
+			.early_init = 1,
+		},
+		.i2c[0] = {
+			.speed = I2C_SPEED_FAST,
+			.rise_time_ns = 88,
+			.fall_time_ns = 16,
+		},
+		.i2c[5] = {
+			.speed = I2C_SPEED_FAST,
+			.rise_time_ns = 104,
+			.fall_time_ns = 52,
+		},
+		.i2c[6] = {
+			.speed = I2C_SPEED_FAST,
+			.rise_time_ns = 66,
+			.fall_time_ns = 90,
+			.data_hold_time_ns = 350,
+		},
+		.i2c[7] = {
+			.speed = I2C_SPEED_FAST,
+			.rise_time_ns = 44,
+			.fall_time_ns = 90,
+		},
+	}"
+
 	device domain 0 on
 		device pci 16.0 on
 			chip drivers/i2c/hid