mb/google/kahlee/variants/baseboard: Set STAPM percentage

Default STAPM percentage causes a lot of thermal throttling on grunt.
AMD experimented with 80%, it works for grunt. This is initial code to
provide easy change path for other grunt based platforms.

BUG=b:111608748
TEST=build and boot grunt.

Change-Id: I22863f6ed76152bf872fce3e275f8a7fd8077504
Signed-off-by: Richard Spiegel <richard.spiegel@silverbackltd.com>
Reviewed-on: https://review.coreboot.org/28564
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

src/soc/amd/stoneyridge/chip.h

@@ -51,6 +51,9 @@ struct soc_amd_stoneyridge_config {
 	size_t uma_size;
 
 	struct dw_i2c_bus_config i2c[STONEY_I2C_DEV_MAX];
+	u8 stapm_percent;
+	u32 stapm_time;
+	u32 stapm_power;
 };
 
 typedef struct soc_amd_stoneyridge_config config_t;