mb/google/sarien: Correct I2C bus clock for touchpad

Elan touchpad require connected i2c clock to be running at 400Khz, with
the modification can get 404Khz speed from Arcada EVT platform.

BUG=b:119628524
TEST=Build and boot up on Arcada platform, measure the i2c clock is
around 400Khz.

Signed-off-by: Lijian Zhao <lijian.zhao@intel.com>
Change-Id: If717cdd6b73394125df54d90f729ffb4ef37b087
Reviewed-on: https://review.coreboot.org/c/30653
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/mainboard/google/sarien/variants/arcada/devicetree.cb

@@ -65,8 +65,8 @@ chip soc/intel/cannonlake
 		},
 		.i2c[1] = {
 			.speed = I2C_SPEED_FAST,
-			.rise_time_ns = 216,
-			.fall_time_ns = 28,
+			.rise_time_ns = 176,
+			.fall_time_ns = 15,
 		},
 		.i2c[4] = {
 			.early_init = 1,