mainboard/google/kahlee: Reset trackpad & touchscreen

AMD chips don't hold off a reset to the end of I2C transitions, so
devices on the i2c bus can be left in a bad state.  To avoid this,
make sure the trackpad and touchscreen chips get disabled
during boot.

BUG=b:114411165
TEST=build, reboot watch trackpad enable go low

Change-Id: Ie50f4a102249df79517da571a6e768dba804cd57
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/28538
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/kahlee/variants/baseboard/gpio.c

@@ -40,6 +40,10 @@ static const struct soc_amd_gpio gpio_set_stage_reset[] = {
 	/* GPIO_15 - EC_IN_RW_OD */
 	PAD_GPI(GPIO_15, PULL_UP),
 
+	/* GPIO_12 - EN_PP3300_TRACKPAD */
+	/* Init low to reset the chip */
+	PAD_GPO(GPIO_12, LOW),
+
 	/* GPIO_22 - EC_SCI_ODL, SCI */
 	PAD_SCI(GPIO_22, PULL_UP, EDGE_LOW),
 
@@ -58,6 +62,10 @@ static const struct soc_amd_gpio gpio_set_stage_reset[] = {
 	/* GPIO_74 - LPC_CLK0_EC_R */
 	PAD_NF(GPIO_74, LPCCLK0, PULL_DOWN),
 
+	/* GPIO_76 - EN_PP3300_TOUCHSCREEN */
+	/* Init low to reset the chip */
+	PAD_GPO(GPIO_76, LOW),
+
 	/* GPIO_92 - WLAN_PCIE_CLKREQ_3V3_ODL */
 	PAD_NF(GPIO_92, CLK_REQ0_L, PULL_UP),