mb/google/brya/var/kano: adjust I2C3 speed

This change adjusts I2C3 speed to lower then 400KHz.

BUG=b:215095284
BRANCH=None
TEST=built and verified adjusted I2C3 speed < 400KHz

Signed-off-by: David Wu <david_wu@quanta.corp-partner.google.com>
Change-Id: Ief6773bc37931a5393b5b1b8beaeda61d235f133
Reviewed-on: https://review.coreboot.org/c/coreboot/+/61272
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nick Vaccaro <nvaccaro@google.com>

src/mainboard/google/brya/variants/kano/overridetree.cb

@@ -56,7 +56,7 @@ chip soc/intel/alderlake
 			.data_hold_time_ns = 50,
 		},
 		.i2c[3] = {
-			.speed = I2C_SPEED_FAST,
+			.speed = 390000,
 			.rise_time_ns = 650,
 			.fall_time_ns = 400,
 			.data_hold_time_ns = 50,