mb/google/skyrim/var/frostflow: Update I2C setting for touchpad

Update setting for touchpad I2C frequency.
And meet touchpad i2c SPEC (380 ~ 400 kHz).

BUG=b:261159229
TEST=On frostflow, touchpad i2c spec from EE measure
Frequencies: I2C0 (Touchpad): 390.1 kHz

Signed-off-by: John Su <john_su@compal.corp-partner.google.com>
Change-Id: Ied00e43e87404489af2b570206a70b685e554b78
Reviewed-on: https://review.coreboot.org/c/coreboot/+/71564
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Dtrain Hsu <dtrain_hsu@compal.corp-partner.google.com>
Reviewed-by: Frank Wu <frank_wu@compal.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/skyrim/variants/frostflow/overridetree.cb

@@ -22,7 +22,7 @@ chip soc/amd/mendocino
 		.speed_config[0] = {
 			.speed = I2C_SPEED_FAST,
 			.scl_hcnt = 120,
-			.scl_lcnt = 240,
+			.scl_lcnt = 190,
 		}
 	}"