mb/google/brox: Tune Touchpad I2C parameters

Adjust Touchpad I2C fall time configuration such that it meets the
I2C fast mode specification(<= 400KHz).

BUG=b:328670295
TEST=Build Brox firmware and boot to OS. Confirm the I2C bus
frequency(375 KHz), rise(650 ns) and fall(330 ns) times meet the
specification.

Change-Id: I0006bfb9bb5839ffa1248d9f2ea055160ed0936e
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83755
Reviewed-by: Bob Moragues <moragues@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jon Murphy <jpmurphy@google.com>

src/mainboard/google/brox/variants/baseboard/brox/devicetree.cb

@@ -103,7 +103,7 @@ chip soc/intel/alderlake
 		.i2c[0] = {
 			.speed = I2C_SPEED_FAST,
 			.rise_time_ns = 650,
-			.fall_time_ns = 350,
+			.fall_time_ns = 330,
 			.data_hold_time_ns = 50,
 		},
 		.i2c[1] = {